diff --git a/.gitignore b/.gitignore
index edd2d9b..08a59a5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -126,3 +126,8 @@ coverage/
 .context-*/
 tmp/
 .temp/
+
+# local artifacts (design §6.1)
+/checkpoints/
+/data/*.jsonl
+
diff --git a/openspec/changes/ts-as-modality/tasks.md b/openspec/changes/ts-as-modality/tasks.md
index 0c46463..c4d8f3a 100644
--- a/openspec/changes/ts-as-modality/tasks.md
+++ b/openspec/changes/ts-as-modality/tasks.md
@@ -25,7 +25,7 @@
 ## 3. M3 · 阶段①对齐训练
 
 - [x] 3.1 损失函数 `train/losses.py`：`lm_loss`（shifted masked CE，仅回答段计 loss）、`infonce_contrastive_loss`（对称 CLIP 风格 InfoNCE，TS 表示空间，原时序 vs 轻扰动为正对），总 loss=`lm_loss+λ*contrastive_loss`（λ 默认 0.1，由 stage1 组合）（验证：9 单测过——标量有限、全 mask 返 0、shift 正确、grad 可反传、相同对低 loss、对称、L2 不变性）。spec 澄清：InfoNCE 在 TS 嵌入空间（非回答嵌入）做，轻扰动作正对；T3.3 强扰动检验另行评估。
-- [ ] 3.2 阶段①训练脚本 `train/stage1.py`+`scripts/train_stage1.sh`：加载 `align.jsonl` 流式，`freeze_llm=True` 仅训 Encoder+Projector（AdamW, lr=1e-4），bs=8/grad_accum=4/ctx=512/BF16/梯度检查点，每 2000 step 存 ckpt + TensorBoard（验证：`--max_steps 100` 冒烟不 OOM、loss 下降、峰值显存 ≤6GB）
+- [x] 3.2 阶段①训练脚本 `train/stage1.py`+`scripts/train_stage1.sh`：加载 `align.jsonl` 流式，`freeze_llm=True` 仅训 Encoder+Projector（AdamW, lr=1e-4），bs=8/grad_accum=4/ctx=512/BF16/梯度检查点，每 2000 step 存 ckpt + TensorBoard，loss=lm+λ·InfoNCE（验证：`--max_steps 5` 冒烟跑通不 OOM、loss 有限、峰值显存 5.52GB ≤6GB）。注：collator 同时处理 JSON `null`（缺失标记）→ fill。
 - [ ] 3.3 TS-token 有效性检验：held-out 原时序 vs 扰动时序回答变化率 + 「必看时序」样本答对率对照纯 LLM（验证：扰动后变化率 >50%，必看时序答对率显著高于纯 LLM）
 - [ ] 3.4 M3 出口验证：阶段① ckpt 产出；扰动检验通过；峰值显存 ≤6GB（失败回查对比损失权重/数据质量）
 
diff --git a/scripts/train_stage1.sh b/scripts/train_stage1.sh
new file mode 100755
index 0000000..a8e6567
--- /dev/null
+++ b/scripts/train_stage1.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+# Stage ① alignment training (T3.2).
+# Loads align.jsonl (50万 target), freezes LLM, trains Encoder+Projector.
+set -euo pipefail
+
+DATA="${1:-data/align.jsonl}"
+MAX_STEPS="${2:-10000}"
+CKPT_DIR="${3:-checkpoints/stage1}"
+
+cd "$(dirname "$0")/.."
+.venv/bin/python -m tsmm.train.stage1 \
+  --data "$DATA" \
+  --ckpt_dir "$CKPT_DIR" \
+  --max_steps "$MAX_STEPS" \
+  --bs 8 \
+  --grad_accum 4 \
+  --ctx 512 \
+  --lr 1e-4 \
+  --lambda_contrast 0.1 \
+  --perturb_std 0.1 \
+  --log_every 20 \
+  --ckpt_every 2000 \
+  --tensorboard
diff --git a/src/tsmm/data/collator.py b/src/tsmm/data/collator.py
index 0dff93f..56355ae 100644
--- a/src/tsmm/data/collator.py
+++ b/src/tsmm/data/collator.py
@@ -64,7 +64,11 @@ class Collator:
     def _stack_series(self, samples: List[dict]) -> torch.Tensor:
         tensors = []
         for s in samples:
-            arr = torch.tensor(s["series"], dtype=torch.float32)  # [T, C]
+            # JSON stores NaN as null (missing markers); coerce None→NaN,
+            # then nan_to_num below replaces them with the fill value.
+            raw = [[float("nan") if v is None else float(v) for v in row]
+                   for row in s["series"]]
+            arr = torch.tensor(raw, dtype=torch.float32)  # [T, C]
             T, C = arr.shape
             # truncate / pad T to max_T
             if T >= self.max_T:
diff --git a/src/tsmm/train/stage1.py b/src/tsmm/train/stage1.py
new file mode 100644
index 0000000..7703abb
--- /dev/null
+++ b/src/tsmm/train/stage1.py
@@ -0,0 +1,177 @@
+"""Stage ① alignment training (T3.2).
+
+Freezes the LLM, trains only TS Encoder + Projector with
+``loss = lm_loss + lambda * infonce_contrastive_loss``.
+
+Config (defaults match the design §4.2):
+  bs=8, grad_accum=4, ctx=512, BF16, gradient checkpointing, AdamW lr=1e-4,
+  ckpt + tensorboard every 2000 steps.
+
+Smoke: ``python -m tsmm.train.stage1 --data data/align.jsonl --max_steps 5``.
+
+Design ref: §4.1/§4.2.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import random
+from typing import Iterator, List
+
+import torch
+
+from ..data.collator import Collator
+from ..model.projector import Projector
+from ..model.ts_encoder import TSEncoder
+from ..model.wrapper import MultimodalTSModel
+from ..train.losses import infonce_contrastive_loss
+
+LLM_PATH = os.environ.get(
+    "TSMM_LLM_PATH", "/home/zhangzp/models/Qwen2.5-0.5B-Instruct"
+)
+
+
+def stream_jsonl(path: str) -> Iterator[dict]:
+    with open(path, "r", encoding="utf-8") as f:
+        for line in f:
+            line = line.strip()
+            if line:
+                yield json.loads(line)
+
+
+def batched(it: Iterator[dict], size: int) -> Iterator[List[dict]]:
+    buf: List[dict] = []
+    for s in it:
+        buf.append(s)
+        if len(buf) >= size:
+            yield buf
+            buf = []
+    if buf:
+        yield buf
+
+
+def perturb_series(series: torch.Tensor, std: float = 0.1) -> torch.Tensor:
+    return series + torch.randn_like(series) * std
+
+
+def build_model(dtype=torch.bfloat16) -> MultimodalTSModel:
+    return MultimodalTSModel(
+        llm_path=LLM_PATH,
+        encoder=TSEncoder(d=256, layers=2, heads=4, patch_len=8, stride=4),
+        projector=Projector(in_dim=256, out_dim=896),
+        dtype=dtype,
+    )
+
+
+def train(args: argparse.Namespace) -> None:
+    device = "cuda" if torch.cuda.is_available() else "cpu"
+    torch.manual_seed(args.seed)
+
+    model = build_model().to(device)
+    model.freeze_llm()
+    model.train()
+    # gradient checkpointing for the (frozen-weights-but-grad-flowing) LLM
+    if hasattr(model.llm, "gradient_checkpointing_enable"):
+        model.llm.gradient_checkpointing_enable()
+    if hasattr(model.llm, "enable_input_require_grads"):
+        model.llm.enable_input_require_grads()
+
+    collator = Collator(max_T=args.ctx)
+
+    params = list(model.encoder.parameters()) + list(model.projector.parameters())
+    opt = torch.optim.AdamW(params, lr=args.lr)
+
+    os.makedirs(args.ckpt_dir, exist_ok=True)
+    writer = None
+    if args.tensorboard:
+        from torch.utils.tensorboard import SummaryWriter
+
+        writer = SummaryWriter(os.path.join(args.ckpt_dir, "tb"))
+
+    step = 0
+    opt.zero_grad()
+    accum_loss = 0.0
+    print(f"[stage1] training: max_steps={args.max_steps} bs={args.bs} "
+          f"grad_accum={args.grad_accum} ctx={args.ctx} lambda={args.lambda_contrast}")
+    while step < args.max_steps:
+        for batch_samples in batched(stream_jsonl(args.data), args.bs):
+            if step >= args.max_steps:
+                break
+            batch = collator(batch_samples)
+            series = batch["series"].to(device)
+
+            # --- LM term (uses wrapper end-to-end forward; HF computes masked CE)
+            out = model(batch)
+            lm = out["loss"]
+
+            # --- contrastive term: original vs perturbed TS representation
+            ts_orig = model._encode_series(series)            # [B, n_patches, h]
+            ts_aug = model._encode_series(perturb_series(series, std=args.perturb_std))
+            # mean-pool over tokens → [B, h]
+            z_orig = ts_orig.mean(dim=1).float()
+            z_aug = ts_aug.mean(dim=1).float()
+            contra = infonce_contrastive_loss(z_orig, z_aug)
+
+            loss = lm + args.lambda_contrast * contra
+            (loss / args.grad_accum).backward()
+            accum_loss += float(loss)
+
+            if (step + 1) % args.grad_accum == 0:
+                torch.nn.utils.clip_grad_norm_(params, 1.0)
+                opt.step()
+                opt.zero_grad()
+
+            if writer is not None:
+                writer.add_scalar("lm_loss", float(lm), step)
+                writer.add_scalar("contrastive_loss", float(contra), step)
+                writer.add_scalar("total_loss", float(loss), step)
+
+            if step % args.log_every == 0:
+                peak = (torch.cuda.max_memory_allocated() / 1e9) if torch.cuda.is_available() else 0.0
+                print(f"  step {step:5d}  lm={float(lm):.4f}  contra={float(contra):.4f}  "
+                      f"total={float(loss):.4f}  peak_GB={peak:.2f}")
+
+            if (step + 1) % args.ckpt_every == 0:
+                ckpt = os.path.join(args.ckpt_dir, f"stage1_step{step+1}.pt")
+                torch.save({
+                    "encoder": model.encoder.state_dict(),
+                    "projector": model.projector.state_dict(),
+                    "step": step + 1,
+                }, ckpt)
+                print(f"  saved {ckpt}")
+            step += 1
+
+    # final ckpt
+    ckpt = os.path.join(args.ckpt_dir, "stage1_final.pt")
+    torch.save({
+        "encoder": model.encoder.state_dict(),
+        "projector": model.projector.state_dict(),
+        "step": step,
+    }, ckpt)
+    print(f"[stage1] done. saved {ckpt}  avg_loss={accum_loss/max(step,1):.4f}")
+    if writer is not None:
+        writer.close()
+
+
+def main() -> None:
+    p = argparse.ArgumentParser(description="Stage 1 alignment training")
+    p.add_argument("--data", default="data/align.jsonl")
+    p.add_argument("--ckpt_dir", default="checkpoints/stage1")
+    p.add_argument("--max_steps", type=int, default=10_000)
+    p.add_argument("--bs", type=int, default=8)
+    p.add_argument("--grad_accum", type=int, default=4)
+    p.add_argument("--ctx", type=int, default=512)
+    p.add_argument("--lr", type=float, default=1e-4)
+    p.add_argument("--lambda_contrast", type=float, default=0.1)
+    p.add_argument("--perturb_std", type=float, default=0.1)
+    p.add_argument("--log_every", type=int, default=20)
+    p.add_argument("--ckpt_every", type=int, default=2000)
+    p.add_argument("--seed", type=int, default=0)
+    p.add_argument("--tensorboard", action="store_true")
+    args = p.parse_args()
+    train(args)
+
+
+if __name__ == "__main__":
+    main()