diff --git a/imperative/python/megengine/device.py b/imperative/python/megengine/device.py
index 008920fe..731b8985 100644
--- a/imperative/python/megengine/device.py
+++ b/imperative/python/megengine/device.py
@@ -17,8 +17,6 @@ __all__ = [
     "set_default_device",
 ]
 
-_default_device = os.getenv("MGE_DEFAULT_DEVICE", "xpux")
-
 
 def _valid_device(inp):
     if isinstance(inp, str) and len(inp) == 4:
@@ -76,9 +74,8 @@ def set_default_device(device: str = "xpux"):
 
         It can also be set by environmental variable `MGE_DEFAULT_DEVICE`.
     """
-    global _default_device  # pylint: disable=global-statement
     assert _valid_device(device), "Invalid device name {}".format(device)
-    _default_device = device
+    CompNode._set_default_device(device)
 
 
 def get_default_device() -> str:
@@ -86,4 +83,7 @@ def get_default_device() -> str:
 
     It returns the value set by :func:`~.set_default_device`.
     """
-    return _default_device
+    return CompNode._get_default_device()
+
+
+set_default_device(os.getenv("MGE_DEFAULT_DEVICE", "xpux"))
diff --git a/imperative/python/src/common.cpp b/imperative/python/src/common.cpp
index 10807a2e..cdaaf819 100644
--- a/imperative/python/src/common.cpp
+++ b/imperative/python/src/common.cpp
@@ -39,13 +39,25 @@ auto def_TensorND(py::object parent, const char* name) {
             &XTensorND::template copy_from_fixlayout<HostTensorStorage>));
 }
 
+std::string default_device = "xpux";
+
 } // namespace
 
+void set_default_device(const std::string &device) {
+    default_device = device;
+}
+
+std::string get_default_device() {
+    return default_device;
+}
+
 void init_common(py::module m) {
     auto&& PyCompNode = py::class_<CompNode>(m, "CompNode")
         .def(py::init())
         .def(py::init(py::overload_cast<const std::string&>(&CompNode::load)))
         .def("create_event", &CompNode::create_event, py::arg("flags") = 0ul)
+        .def("_set_default_device", &set_default_device)
+        .def("_get_default_device", &get_default_device)
         .def("__str__", &CompNode::to_string_logical)
         .def_static("_sync_all", &CompNode::sync_all)
         .def(py::self == py::self)
diff --git a/imperative/python/src/common.h b/imperative/python/src/common.h
index 5837de34..d5201b19 100644
--- a/imperative/python/src/common.h
+++ b/imperative/python/src/common.h
@@ -14,3 +14,6 @@
 #include "./helper.h"
 
 void init_common(pybind11::module m);
+
+void set_default_device(const std::string &device);
+std::string get_default_device();
\ No newline at end of file
diff --git a/imperative/python/src/graph_rt.cpp b/imperative/python/src/graph_rt.cpp
index deb29bba..500d8dd3 100644
--- a/imperative/python/src/graph_rt.cpp
+++ b/imperative/python/src/graph_rt.cpp
@@ -19,6 +19,7 @@
 #include "megbrain/imperative.h"
 #include "./helper.h"
 #include "megbrain/plugin/profiler.h"
+#include "./common.h"
 
 namespace py = pybind11;
 
@@ -230,7 +231,7 @@ void init_graph_rt(py::module m) {
 
     m.def("make_const", [](cg::ComputingGraph* graph, py::array data, CompNode cn, DType dtype) {
             if (!cn.valid()) {
-                cn = CompNode::load("xpux");
+                cn = CompNode::load(get_default_device());
             }
             auto hv = npy::np2tensor(data.ptr(), npy::Meth::borrow(cn), dtype);
             return opr::ImmutableTensor::make(*graph, hv, OperatorNodeConfig(cn)).node();
diff --git a/imperative/python/src/imperative_rt.cpp b/imperative/python/src/imperative_rt.cpp
index 6055b411..c96efbfe 100644
--- a/imperative/python/src/imperative_rt.cpp
+++ b/imperative/python/src/imperative_rt.cpp
@@ -21,6 +21,7 @@
 #include "megbrain/imperative/interpreter.h"
 #include "megbrain/imperative/ops/opr_attr.h"
 #include "./helper.h"
+#include "./common.h"
 
 namespace py = pybind11;
 
@@ -53,7 +54,7 @@ void init_imperative_rt(py::module m) {
     py::class_<Interpreter::Channel>(m, "Interpreter")
         .def("put", [](Interpreter::Channel& self, py::array data, DType dtype, CompNode cn) {
                 if (!cn.valid()) {
-                    cn = CompNode::load("xpux");
+                    cn = CompNode::load(get_default_device());
                 }
                 constexpr int size_threshhold = TensorShape::MAX_NDIM;
                 if (data.size() > size_threshhold) {