diff --git a/pyproject.toml b/pyproject.toml
index 3dc57d9..d300a12 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,6 +10,7 @@ dependencies = [
     "pandas>=2.0",
     "numpy>=1.24",
     "matplotlib>=3.7",
+    "Pillow>=10.0",
 ]
 
 [project.scripts]
diff --git a/tests/test_montage.py b/tests/test_montage.py
new file mode 100644
index 0000000..6770d29
--- /dev/null
+++ b/tests/test_montage.py
@@ -0,0 +1,57 @@
+"""montage_pngs 单元测试。"""
+
+import tempfile
+from pathlib import Path
+
+from PIL import Image
+
+
+def _make_test_png(path, w=200, h=100, color="red"):
+    """创建测试用 PNG。"""
+    img = Image.new("RGB", (w, h), color)
+    img.save(path)
+    return str(path)
+
+
+def test_montage_basic():
+    """4 张图拼成 2x2 网格。"""
+    from ts_anomaly_td.visualize import montage_pngs
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        paths = []
+        for i, color in enumerate(["red", "green", "blue", "yellow"]):
+            p = Path(tmpdir) / f"img_{i}.png"
+            _make_test_png(p, color=color)
+            paths.append(str(p))
+
+        out = Path(tmpdir) / "montage.png"
+        result = montage_pngs(paths, str(out), cols=2, title="Test")
+        assert Path(result).exists()
+        assert Path(result).stat().st_size > 1000
+
+
+def test_montage_uneven():
+    """3 张图拼成 2 列（第二行只 1 张）。"""
+    from ts_anomaly_td.visualize import montage_pngs
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        paths = []
+        for i in range(3):
+            p = Path(tmpdir) / f"img_{i}.png"
+            _make_test_png(p)
+            paths.append(str(p))
+
+        out = Path(tmpdir) / "montage_uneven.png"
+        result = montage_pngs(paths, str(out), cols=2)
+        assert Path(result).exists()
+
+
+def test_montage_empty():
+    """空列表应抛 ValueError。"""
+    from ts_anomaly_td.visualize import montage_pngs
+
+    try:
+        montage_pngs([], "/dev/null")
+        assert False, "应抛 ValueError"
+    except ValueError:
+        pass
diff --git a/ts_anomaly_td/cli.py b/ts_anomaly_td/cli.py
index b4828fc..f3387f9 100644
--- a/ts_anomaly_td/cli.py
+++ b/ts_anomaly_td/cli.py
@@ -218,6 +218,13 @@ def build_parser() -> argparse.ArgumentParser:
     p_ra.add_argument("--value-col", default="value", help="数值列名 (default: value)")
     p_ra.add_argument("--title", default="", help="图表标题")
 
+    # montage
+    p_mt = sub.add_parser("montage", help="多 PNG 拼图")
+    p_mt.add_argument("--inputs", nargs="+", required=True, help="输入 PNG 文件列表")
+    p_mt.add_argument("--output", required=True, help="拼图输出路径")
+    p_mt.add_argument("--cols", type=int, default=2, help="列数 (default: 2)")
+    p_mt.add_argument("--title", default="", help="总标题")
+
     return parser
 
 
@@ -241,6 +248,16 @@ def cmd_render_algo(args):
     render_algo(ts, vals, labels, windows, args.algo, args.output, title=title)
 
 
+def cmd_montage(args):
+    """montage 子命令：多 PNG 拼图。"""
+    logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(message)s")
+
+    from ts_anomaly_td.visualize import montage_pngs
+
+    montage_pngs(args.inputs, args.output, cols=args.cols, title=args.title)
+    logger.info("montage complete: %s", args.output)
+
+
 def main():
     parser = build_parser()
     args = parser.parse_args()
@@ -253,6 +270,7 @@ def main():
         "visualize": cmd_visualize,
         "watch": cmd_watch,
         "render-algo": cmd_render_algo,
+        "montage": cmd_montage,
     }
 
     fn = dispatch.get(args.command)