diff --git a/src/memos/multi_mem_cube/single_cube.py b/src/memos/multi_mem_cube/single_cube.py
index 6a91f436f..355cb8cee 100644
--- a/src/memos/multi_mem_cube/single_cube.py
+++ b/src/memos/multi_mem_cube/single_cube.py
@@ -22,7 +22,7 @@
 )
 from memos.memories.textual.item import TextualMemoryItem
 from memos.multi_mem_cube.views import MemCubeView
-from memos.search import search_text_memories
+from memos.search import resolve_filter_for_cube, search_text_memories
 from memos.templates.mem_reader_prompts import PROMPT_MAPPING
 from memos.types.general_types import (
     FINE_STRATEGY,
@@ -91,6 +91,13 @@ def search_memories(self, search_req: APISearchRequest) -> dict[str, Any]:
         Unified memory search handling (text + preference memories).
         Preference memories are now searched through the same _search_text flow.
         """
+        cube_filter = resolve_filter_for_cube(search_req.filter, self.cube_id)
+        if cube_filter is not search_req.filter:
+            import copy
+
+            search_req = copy.copy(search_req)
+            search_req.filter = cube_filter
+
         # Create UserContext object
         user_context = UserContext(
             user_id=search_req.user_id,
diff --git a/src/memos/search/__init__.py b/src/memos/search/__init__.py
index 71388c62b..d2c197403 100644
--- a/src/memos/search/__init__.py
+++ b/src/memos/search/__init__.py
@@ -1,4 +1,14 @@
-from .search_service import SearchContext, build_search_context, search_text_memories
+from .search_service import (
+    SearchContext,
+    build_search_context,
+    resolve_filter_for_cube,
+    search_text_memories,
+)
 
 
-__all__ = ["SearchContext", "build_search_context", "search_text_memories"]
+__all__ = [
+    "SearchContext",
+    "build_search_context",
+    "resolve_filter_for_cube",
+    "search_text_memories",
+]
diff --git a/src/memos/search/search_service.py b/src/memos/search/search_service.py
index fa713a7d1..f4092d168 100644
--- a/src/memos/search/search_service.py
+++ b/src/memos/search/search_service.py
@@ -36,6 +36,35 @@ def build_search_context(
     )
 
 
+def resolve_filter_for_cube(
+    raw_filter: dict[str, Any] | None, cube_id: str
+) -> dict[str, Any] | None:
+    """Resolve a multi-cube filter dict into the sub-filter for a single cube.
+
+    Supported forms:
+      - None                          → None  (no filter)
+      - {"and": [...]}  / {"or": [...]}  → returned as-is (unified, all cubes share)
+      - {"cube_A": {...}, "cube_B": {...}} → return raw_filter[cube_id] or None
+    Mixed top-level (and/or + cube keys) is rejected.
+    """
+    if raw_filter is None:
+        return None
+
+    has_logic_key = "and" in raw_filter or "or" in raw_filter
+    other_keys = {k for k in raw_filter if k not in ("and", "or")}
+
+    if has_logic_key and other_keys:
+        raise ValueError(
+            "Invalid filter: top-level 'and'/'or' cannot coexist with per-cube keys "
+            f"{other_keys}. Use either a unified filter or per-cube filter, not both."
+        )
+
+    if has_logic_key:
+        return raw_filter
+
+    return raw_filter.get(cube_id)
+
+
 def search_text_memories(
     text_mem: Any,
     search_req: APISearchRequest,
diff --git a/tests/search/test_resolve_filter_for_cube.py b/tests/search/test_resolve_filter_for_cube.py
new file mode 100644
index 000000000..ab6be71a3
--- /dev/null
+++ b/tests/search/test_resolve_filter_for_cube.py
@@ -0,0 +1,78 @@
+import pytest
+
+from memos.search.search_service import resolve_filter_for_cube
+
+
+class TestResolveFilterForCube:
+    """Tests for resolve_filter_for_cube — multi-cube filter routing."""
+
+    # ── None passthrough ──
+
+    def test_none_returns_none(self):
+        assert resolve_filter_for_cube(None, "cube_001") is None
+
+    # ── Unified filter (filter2): top-level and/or ──
+
+    def test_unified_and_returns_same_for_any_cube(self):
+        f = {"and": [{"tags": {"contains": "阅读"}}, {"created_at": {"gte": "2025-01-01"}}]}
+        assert resolve_filter_for_cube(f, "cube_001") is f
+        assert resolve_filter_for_cube(f, "cube_999") is f
+
+    def test_unified_or_returns_same_for_any_cube(self):
+        f = {"or": [{"tags": {"contains": "A"}}, {"tags": {"contains": "B"}}]}
+        assert resolve_filter_for_cube(f, "cube_001") is f
+
+    # ── Per-cube filter (filter1 / filter4) ──
+
+    def test_per_cube_returns_matching_sub_filter(self):
+        sub_a = {"and": [{"tags": {"contains": "阅读"}}]}
+        sub_b = {"and": [{"tags": {"contains": "工作"}}]}
+        f = {"cube_A": sub_a, "cube_B": sub_b}
+
+        assert resolve_filter_for_cube(f, "cube_A") is sub_a
+        assert resolve_filter_for_cube(f, "cube_B") is sub_b
+
+    def test_per_cube_missing_key_returns_none(self):
+        f = {
+            "cube_A": {"and": [{"tags": {"contains": "阅读"}}]},
+            "cube_B": {"and": [{"tags": {"contains": "工作"}}]},
+        }
+        assert resolve_filter_for_cube(f, "cube_C") is None
+
+    def test_per_cube_single_key(self):
+        sub = {"and": [{"created_at": {"gte": "2025-01-01"}}]}
+        f = {"cube_only": sub}
+        assert resolve_filter_for_cube(f, "cube_only") is sub
+        assert resolve_filter_for_cube(f, "other") is None
+
+    # ── Mixed (filter3): illegal ──
+
+    def test_mixed_and_with_cube_key_raises(self):
+        f = {
+            "and": [{"tags": {"contains": "阅读"}}],
+            "cube_A": {"and": [{"tags": {"contains": "工作"}}]},
+        }
+        with pytest.raises(ValueError, match="cannot coexist"):
+            resolve_filter_for_cube(f, "cube_A")
+
+    def test_mixed_or_with_cube_key_raises(self):
+        f = {
+            "or": [{"tags": {"contains": "阅读"}}],
+            "cube_B": {"and": [{"tags": {"contains": "工作"}}]},
+        }
+        with pytest.raises(ValueError, match="cannot coexist"):
+            resolve_filter_for_cube(f, "cube_B")
+
+    # ── Edge cases ──
+
+    def test_empty_dict_returns_none(self):
+        assert resolve_filter_for_cube({}, "cube_001") is None
+
+    def test_per_cube_with_empty_sub_filter(self):
+        f = {"cube_A": {}}
+        result = resolve_filter_for_cube(f, "cube_A")
+        assert result == {}
+
+    def test_unified_and_empty_list(self):
+        f = {"and": []}
+        assert resolve_filter_for_cube(f, "any") is f