diff --git a/imperative/python/megengine/device.py b/imperative/python/megengine/device.py
index f81893c2..2667536f 100644
--- a/imperative/python/megengine/device.py
+++ b/imperative/python/megengine/device.py
@@ -7,6 +7,7 @@
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 import os
+import re
 
 from .core._imperative_rt.common import CompNode, DeviceType
 from .core._imperative_rt.common import set_prealloc_config as _set_prealloc_config
@@ -22,10 +23,8 @@ __all__ = [
 
 
 def _valid_device(inp):
-    if isinstance(inp, str) and len(inp) == 4:
-        if inp[0] in {"x", "c", "g"} and inp[1:3] == "pu":
-            if inp[3] == "x" or inp[3].isdigit():
-                return True
+    if isinstance(inp, str) and re.match("^[cxg]pu(\d+|\d+:\d+|x)$", inp):
+        return True
     return False
 
 
diff --git a/imperative/python/megengine/tensor.py b/imperative/python/megengine/tensor.py
index a8eae821..0d30a264 100644
--- a/imperative/python/megengine/tensor.py
+++ b/imperative/python/megengine/tensor.py
@@ -14,7 +14,7 @@ from .core import Tensor as _Tensor
 from .core.ops.builtin import Copy
 from .core.tensor.core import apply
 from .core.tensor.raw_tensor import as_device
-from .device import get_default_device
+from .device import _valid_device, get_default_device
 from .utils.deprecation import deprecated
 
 
@@ -37,6 +37,12 @@ class Tensor(_Tensor):
         self *= 0
 
     def to(self, device):
+        if isinstance(device, str) and not _valid_device(device):
+            raise ValueError(
+                "invalid device name {}. For the correct format of the device name, please refer to the instruction of megengine.device.set_default_device()".format(
+                    device
+                )
+            )
         cn = as_device(device).to_c()
         return apply(Copy(comp_node=cn), self)[0]