diff --git a/imperative/python/megengine/traced_module/expr.py b/imperative/python/megengine/traced_module/expr.py
index cc486b0a..19624482 100644
--- a/imperative/python/megengine/traced_module/expr.py
+++ b/imperative/python/megengine/traced_module/expr.py
@@ -606,7 +606,8 @@ class Apply(Expr):
     def apply_module_trace_hook(cls, opdef, *inputs):
         for i in inputs:
             node = NodeMixin.get(i, None)
-            assert node is not None
+            if node is None:  # capture as constant
+                NodeMixin.wrap_safe(i, Constant.make(i))
 
         if isinstance(opdef, FakeQuant):
             inp_nodes = [NodeMixin.get(inputs[0])]
@@ -627,7 +628,6 @@ class Apply(Expr):
 
         unset_module_tracing()
         outputs = apply(opdef, *inputs)
-        outputs = list(map(Tensor, outputs))
         set_module_tracing()
 
         apply_node.add_outputs(outputs)
@@ -741,12 +741,8 @@ class Constant(Expr):
         assert isinstance(c, (RawTensor, Module))
         if isinstance(c, Module):
             assert module_tracer.is_builtin(c) or c.is_qat
-        if isinstance(c, RawTensor):
-            if is_tracing_module():
-                unset_module_tracing()
-                c = Tensor(c)
-                set_module_tracing()
-            else:
+        if type(c) is RawTensor:
+            with _exclude_from_trace():
                 c = Tensor(c)
         self.value = c
         self.name = name
diff --git a/imperative/python/src/module_trace.h b/imperative/python/src/module_trace.h
index 410900ec..eee35d6c 100644
--- a/imperative/python/src/module_trace.h
+++ b/imperative/python/src/module_trace.h
@@ -52,6 +52,12 @@ public:
         }
     }
 
+    void enable() { m_enabled = 1; }
+
+    void disable() { m_enabled = 0; }
+
+    bool enabled() const { return m_enabled; }
+
     ValueRef unwrap(ValueRef value) override { return value; }
 
     std::string name() const override { return "ModuleTraceTransformation"; }
diff --git a/imperative/python/src/tensor.cpp b/imperative/python/src/tensor.cpp
index 4d7b6767..8cede64a 100644
--- a/imperative/python/src/tensor.cpp
+++ b/imperative/python/src/tensor.cpp
@@ -219,17 +219,19 @@ TensorWrapper::TensorWrapper(PyObject* args, PyObject* kwargs) {
 
 PyObject* TensorWrapper::module_trace_info() {
     if (auto module_trace_info = module_trace_info_map.try_get(m_tensor->data())) {
-        return module_trace_info->inc_ref().ptr();
-    } else {
-        PyErr_SetString(
-                PyExc_AttributeError,
-                "Has no attribute named \'_NodeMixin__node\', please "
-                "set it first");
-        return nullptr;
+        if (module_trace_info->ptr()) {
+            return module_trace_info->inc_ref().ptr();
+        }
     }
+    PyErr_SetString(
+            PyExc_AttributeError,
+            "Has no attribute named \'_NodeMixin__node\', please "
+            "set it first");
+    return nullptr;
 }
 
 void TensorWrapper::set_module_trace_info(PyObject* obj) {
+    // TODO: erase when obj == nullptr
     module_trace_info_map[m_tensor->data()] = py::reinterpret_borrow<py::object>(obj);
 }
 
@@ -1031,29 +1033,23 @@ void init_tensor(py::module m) {
 
     static py::function module_trace_hook;
 
-    static std::shared_ptr<ModuleTraceTransformation> module_trace_transformation;
-    static int module_tracing = 0;
-
-    m.def("set_module_tracing", [=] {
+    static auto get_module_trace = [] {
+        static std::shared_ptr<ModuleTraceTransformation> module_trace_transformation;
         if (!module_trace_transformation) {
             mgb_assert(module_trace_hook);
             module_trace_transformation =
                     std::make_shared<ModuleTraceTransformation>(module_trace_hook);
-        }
-        if (++module_tracing == 1) {
-            transformations.register_at<TransformationManager::ModuleTrace>(
+            transformations.register_at<Segment::ModuleTrace>(
                     module_trace_transformation);
         }
-    });
+        return module_trace_transformation;
+    };
 
-    m.def("unset_module_tracing", [=] {
-        if (--module_tracing == 0) {
-            transformations.unregister<TransformationManager::ModuleTrace>(
-                    module_trace_transformation);
-        }
-    });
+    m.def("set_module_tracing", [=] { get_module_trace()->enable(); });
+
+    m.def("unset_module_tracing", [=] { get_module_trace()->disable(); });
 
-    m.def("is_tracing_module", [=] { return module_tracing > 0; });
+    m.def("is_tracing_module", [=] { return get_module_trace()->enabled(); });
 
     m.def("set_module_trace_hook",
           [](py::function function) { module_trace_hook = function; });
diff --git a/imperative/python/test/unit/traced_module/test_trace_module.py b/imperative/python/test/unit/traced_module/test_trace_module.py
index d3baf153..43d3f492 100644
--- a/imperative/python/test/unit/traced_module/test_trace_module.py
+++ b/imperative/python/test/unit/traced_module/test_trace_module.py
@@ -5,9 +5,11 @@ import numpy as np
 import megengine.functional as F
 import megengine.module as M
 from megengine import Tensor
-from megengine.module.module import Module
+from megengine.core._imperative_rt.core2 import apply
+from megengine.core.ops import builtin
+from megengine.module import Module
 from megengine.traced_module import TracedModule, enable_expr_checker, trace_module
-from megengine.traced_module.expr import CallFunction
+from megengine.traced_module.expr import Apply, CallFunction, Constant
 
 
 class MyModule1(M.Module):
@@ -133,3 +135,25 @@ def test_trace_module():
     tm6 = trace_module(MyModule5(), a, b)
     assert tm6.m1.argspec is None
     assert tm6.m1._is_top is False
+
+
+def test_trace_module_2():
+    class Model(M.Module):
+        def __init__(self):
+            super().__init__()
+
+        def forward(self, x):
+            out = x.shape
+            out = apply(builtin.Elemwise(mode="ADD"), out, Tensor(1))
+            return out
+
+    traced_model = trace_module(Model(), Tensor(([1,])))
+
+    assert isinstance(traced_model.graph._exprs[0], Apply) and isinstance(
+        traced_model.graph._exprs[0].opdef, builtin.GetVarShape
+    )
+    assert isinstance(traced_model.graph._exprs[1], Constant)
+    assert isinstance(traced_model.graph._exprs[2], Apply) and isinstance(
+        traced_model.graph._exprs[2].opdef, builtin.Elemwise
+    )
+    assert int(traced_model(Tensor([1, 2]))[0]) == 3