diff --git a/dnn/include/megdnn/dtype.h b/dnn/include/megdnn/dtype.h
index aae14fec..df3319f0 100644
--- a/dnn/include/megdnn/dtype.h
+++ b/dnn/include/megdnn/dtype.h
@@ -132,6 +132,15 @@ namespace megdnn {
     cb(::megdnn::dtype::Quantized4Asymm) \
     cb(::megdnn::dtype::QuantizedS4)
 
+#define MEGDNN_FOREACH_QUANTIZED_DTYPE_SYMM(cb) \
+    cb(::megdnn::dtype::QuantizedS32) \
+    cb(::megdnn::dtype::QuantizedS8) \
+    cb(::megdnn::dtype::QuantizedS4)
+
+#define MEGDNN_FOREACH_QUANTIZED_DTYPE_ASYMM(cb) \
+    cb(::megdnn::dtype::Quantized8Asymm) \
+    cb(::megdnn::dtype::Quantized4Asymm)
+
 /*!
  * \brief a POD representation of a single byte
  *
diff --git a/dnn/src/common/convolution.cpp b/dnn/src/common/convolution.cpp
index 41b1249a..0a89010f 100644
--- a/dnn/src/common/convolution.cpp
+++ b/dnn/src/common/convolution.cpp
@@ -604,9 +604,16 @@ void ConvolutionBase<Parameter>::check_or_deduce_dtype_fwd(DType src,
     if (!dst.valid()) {
         dst = supported_dst_dtype.at(0);
     } else {
-        megdnn_assert(vec_contains(supported_dst_dtype, dst),
-                      "unsupported Conv(%s, %s) -> %s", src.name(),
-                      filter.name(), dst.name());
+        bool dst_supported = false;
+        for (auto&& dt : supported_dst_dtype) {
+            if (dtype_almost_equal(dt, dst)) {
+                dst_supported = true;
+                break;
+            }
+        }
+        MEGDNN_MARK_USED_VAR(dst_supported);
+        megdnn_assert(dst_supported, "unsupported Conv(%s, %s) -> %s",
+                      src.name(), filter.name(), dst.name());
     }
     megdnn_assert(param().compute_mode != Param::ComputeMode::FLOAT32
 #if !MEGDNN_DISABLE_FLOAT16
diff --git a/dnn/src/common/utils.cpp b/dnn/src/common/utils.cpp
index 371afbb5..2dd2ca70 100644
--- a/dnn/src/common/utils.cpp
+++ b/dnn/src/common/utils.cpp
@@ -245,6 +245,25 @@ float megdnn::mul_scale(DType lhs, DType rhs) {
 }
 // clang-format on
 
+bool megdnn::dtype_almost_equal(DType lhs, DType rhs) {
+    if (lhs.enumv() != rhs.enumv())
+        return false;
+    if (lhs.category() != DTypeCategory::QUANTIZED)
+        return true;
+#define cb(dt)                                \
+    if (lhs.enumv() == DTypeTrait<dt>::enumv) \
+        return almost_equal(lhs.param<dt>().scale, rhs.param<dt>().scale);
+    MEGDNN_FOREACH_QUANTIZED_DTYPE_SYMM(cb)
+#undef cb
+#define cb(dt)                                                               \
+    if (lhs.enumv() == DTypeTrait<dt>::enumv)                                \
+        return almost_equal(lhs.param<dt>().scale, rhs.param<dt>().scale) && \
+               lhs.param<dt>().zero_point == rhs.param<dt>().zero_point;
+    MEGDNN_FOREACH_QUANTIZED_DTYPE_ASYMM(cb)
+#undef cb
+    megdnn_assert_internal(false);
+}
+
 template <>
 uint8_t megdnn::convert<dt_quint4, uint8_t>(dt_quint4 src, uint8_t dst,
                                             size_t offset) {
diff --git a/dnn/src/common/utils.h b/dnn/src/common/utils.h
index a12f2a53..1061ab47 100644
--- a/dnn/src/common/utils.h
+++ b/dnn/src/common/utils.h
@@ -434,6 +434,20 @@ int8_t convert<dt_qint4, int8_t>(dt_qint4 src, int8_t dst, size_t offset);
 template <>
 dt_qint4 convert<int8_t, dt_qint4>(int8_t src, dt_qint4 dst, size_t offset);
 
+/*!
+ * \brief check float equal within given ULP(unit in the last place)
+ */
+template <class T>
+static inline
+        typename std::enable_if<!std::numeric_limits<T>::is_integer, bool>::type
+        almost_equal(T x, T y, int unit_last_place = 1) {
+    return std::abs(x - y) < (std::numeric_limits<T>::epsilon() *
+                              std::abs(x + y) * unit_last_place) ||
+           std::abs(x - y) < std::numeric_limits<T>::min();
+}
+
+bool dtype_almost_equal(DType lhs, DType rhs);
+
 /**
  * \brief N-dimensional index space
  */