diff --git a/imperative/python/megengine/module/quantized/concat.py b/imperative/python/megengine/module/quantized/concat.py
index 11af852913f7430b27688663eb65808f39159a54..7fef963e827d65340cea443b702526fd2b716b63 100644
--- a/imperative/python/megengine/module/quantized/concat.py
+++ b/imperative/python/megengine/module/quantized/concat.py
@@ -23,7 +23,7 @@ class Concat(QuantizedModule):
         self.output_dtype = dtype
 
     def forward(self, inps: Iterable[Tensor], axis: int = 0):
-        new_inps = (x.astype(self.output_dtype) for x in inps)
+        new_inps = tuple(x.astype(self.output_dtype) for x in inps)
         return F.concat(new_inps, axis)
 
     @classmethod
diff --git a/imperative/python/megengine/quantization/__init__.py b/imperative/python/megengine/quantization/__init__.py
index d33de8d7b328debc989d1693b3766c404baf5a03..2d6bf959b3b460152db31a5755728e6fe5439eb9 100644
--- a/imperative/python/megengine/quantization/__init__.py
+++ b/imperative/python/megengine/quantization/__init__.py
@@ -6,8 +6,16 @@
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 
-from .fake_quant import FakeQuantize
-from .observer import Observer
+from .fake_quant import TQT, FakeQuantize
+from .observer import (
+    ExponentialMovingAverageObserver,
+    HistogramObserver,
+    MinMaxObserver,
+    Observer,
+    PassiveObserver,
+    SyncExponentialMovingAverageObserver,
+    SyncMinMaxObserver,
+)
 from .qconfig import (
     QConfig,
     calibration_qconfig,
diff --git a/imperative/python/test/unit/quantization/test_module.py b/imperative/python/test/unit/quantization/test_module.py
index cfdf03448a6777f4ba627abbccda487694118d4d..bbb95cff6eb92a69e4eb21ef290865c86bea3ab1 100644
--- a/imperative/python/test/unit/quantization/test_module.py
+++ b/imperative/python/test/unit/quantization/test_module.py
@@ -30,7 +30,10 @@ min_max_fakequant_qconfig = QConfig(
     act_fake_quant=partial(FakeQuantize, dtype="qint8"),
 )
 
-inp_scale = np.float32(np.random.rand() + 1)
+
+def gen_inp_scale():
+    return np.float32(np.random.rand() + 1)
+
 
 min_val = np.random.randint(-127, 0, size=(2,)).astype("float32")
 max_val = np.random.randint(1, 127, size=(2,)).astype("float32")
@@ -116,6 +119,7 @@ def test_dequant_stub():
     q_net.eval()
 
     x = mge.tensor(np.random.normal(size=(3, 3)).astype("float32"))
+    inp_scale = gen_inp_scale()
     x = fake_quant_act(x, inp_scale)
     x.qparams.scale = inp_scale
 
@@ -192,6 +196,7 @@ def test_linear():
     init_qat_net(qat_net)
 
     x = mge.tensor(np.random.normal(size=(3, 3)).astype("float32"))
+    inp_scale = gen_inp_scale()
     x = fake_quant_act(x, inp_scale)
     x.qparams.update(create_qparams(QuantMode.SYMMERTIC, "qint8", inp_scale))
 
@@ -235,6 +240,7 @@ def test_conv(module):
     init_qat_net(qat_net)
 
     x = mge.tensor(np.random.normal(size=(1, 3, 3, 3)).astype("float32"))
+    inp_scale = gen_inp_scale()
     x = fake_quant_act(x, inp_scale)
     x.qparams.update(create_qparams(QuantMode.SYMMERTIC, "qint8", inp_scale))
 
@@ -269,3 +275,41 @@ def test_conv(module):
     np.testing.assert_allclose(qat_without_fakequant, normal, atol=1e-5)
     np.testing.assert_allclose(qat, fake_quant_normal, atol=act_scale)
     np.testing.assert_allclose(q, fake_quant_normal.numpy(), atol=act_scale)
+
+
+def test_concat():
+    normal_net = Float.Concat()
+    normal_net.eval()
+
+    qat_net = QAT.Concat()
+    qat_net.eval()
+    disable_observer(qat_net)
+
+    propagate_qconfig(qat_net, min_max_fakequant_qconfig)
+    init_qat_net(qat_net)
+
+    inps = []
+    inps_int8 = []
+    for i in range(3):
+        inp_scale = gen_inp_scale()
+        inps.append(mge.tensor(np.random.normal(size=(3, 3)).astype("float32")))
+        inps[i] = fake_quant_act(inps[i], inp_scale)
+        inps[i].qparams.update(create_qparams(QuantMode.SYMMERTIC, "qint8", inp_scale))
+        inps_int8.append(quant(inps[i], inp_scale))
+
+    qat_from_float = QAT.Concat.from_float_module(normal_net)
+    qat_from_float.eval()
+    disable_fake_quant(qat_from_float)
+    disable_observer(qat_from_float)
+
+    q_net = Q.Concat.from_qat_module(qat_net)
+    q_net.eval()
+
+    normal = normal_net(inps)
+    qat_without_fakequant = qat_from_float(inps)
+    fake_quant_normal = fake_quant_act(normal_net(inps), act_scale)
+    qat = qat_net(inps)
+    q = q_net(inps_int8).numpy() * act_scale
+    np.testing.assert_allclose(qat_without_fakequant, normal)
+    np.testing.assert_allclose(qat, fake_quant_normal.numpy())
+    np.testing.assert_allclose(q, fake_quant_normal.numpy())