diff --git a/tools/onnx/onnx2ncnn.cpp b/tools/onnx/onnx2ncnn.cpp
index 3b8edc6f3..679cc91f6 100644
--- a/tools/onnx/onnx2ncnn.cpp
+++ b/tools/onnx/onnx2ncnn.cpp
@@ -1824,15 +1824,15 @@ static void fuse_expand_broadcast(onnx::GraphProto* mutable_graph, std::map<std:
     }
 }
 
-static void fuse_bilstm(onnx::GraphProto* mutable_graph, std::map<std::string, onnx::TensorProto>& weights, std::map<std::string, int>& node_reference, std::set<std::string>& blob_names, int& reduced_node_count)
+static void fuse_lstm_gru_rnn(onnx::GraphProto* mutable_graph, std::map<std::string, onnx::TensorProto>& weights, std::map<std::string, int>& node_reference, std::set<std::string>& blob_names, int& reduced_node_count)
 {
     int node_count = mutable_graph->node_size();
     for (int i = 0; i < node_count; i++)
     {
         onnx::NodeProto* node = mutable_graph->mutable_node(i);
 
-        // LSTM <= LSTM - Transpose - Reshape - Transpose
-        if (node->op_type() == "LSTM")
+        // LSTM(bi) <= LSTM(bi) - Transpose - Reshape - Transpose
+        if (node->op_type() == "LSTM" || node->op_type() == "GRU" || node->op_type() == "RNN")
         {
             if (node_reference[node->output(0)] != 1)
                 continue;
@@ -1914,12 +1914,15 @@ static void fuse_bilstm(onnx::GraphProto* mutable_graph, std::map<std::string, o
 
             if (i + 1 < node_count)
             {
+                if (node_reference[node3->output(0)] != 1)
+                    continue;
+
                 onnx::NodeProto* node4 = mutable_graph->mutable_node(i + 1);
 
                 if (node4->op_type() != "Transpose")
                     continue;
 
-                if (node4->input(0) != node3->output(0))
+                if (node4->input(0) != node->output(0))
                     continue;
 
                 // 1 0 2
@@ -1946,6 +1949,96 @@ static void fuse_bilstm(onnx::GraphProto* mutable_graph, std::map<std::string, o
         }
     }
 
+    for (int i = 0; i < node_count; i++)
+    {
+        onnx::NodeProto* node = mutable_graph->mutable_node(i);
+
+        // LSTM(uni) <= LSTM(uni) - Squeeze - Transpose
+        if (node->op_type() == "LSTM" || node->op_type() == "GRU" || node->op_type() == "RNN")
+        {
+            if (node_reference[node->output(0)] != 1)
+                continue;
+
+            if (i + 1 >= node_count)
+                continue;
+
+            onnx::NodeProto* node2 = mutable_graph->mutable_node(i + 1);
+
+            if (node2->op_type() != "Squeeze")
+                continue;
+
+            if (node2->input(0) != node->output(0))
+                continue;
+
+            std::string direction = get_node_attr_s(*node, "direction");
+            if (direction == "bidirectional")
+                continue;
+
+            // 1
+            std::vector<int> axes = get_node_attr_ai(*node2, "axes");
+            if (axes.size() != 1)
+                continue;
+
+            if (axes[0] != 1)
+                continue;
+
+            // reduce
+            node2->set_op_type("noop_reducedncnn");
+
+            node_reference[node->output(0)] -= 1;
+
+            blob_names.erase(node->output(0));
+            if (node->output_size() > 1)
+            {
+                for (int j = 1; j < node->output_size(); j++)
+                {
+                    blob_names.erase(node->output(j));
+                }
+            }
+
+            node->clear_output();
+            node->add_output(node2->output(0));
+
+            reduced_node_count += 1;
+            i += 1;
+
+            if (i + 1 < node_count)
+            {
+                if (node_reference[node2->output(0)] != 1)
+                    continue;
+
+                onnx::NodeProto* node3 = mutable_graph->mutable_node(i + 1);
+
+                if (node3->op_type() != "Transpose")
+                    continue;
+
+                if (node3->input(0) != node->output(0))
+                    continue;
+
+                // 1 0 2
+                std::vector<int> perm4 = get_node_attr_ai(*node3, "perm");
+                if (perm4.size() != 3)
+                    continue;
+
+                if (perm4[0] != 1 || perm4[1] != 0 || perm4[2] != 2)
+                    continue;
+
+                // reduce
+                node3->set_op_type("noop_reducedncnn");
+
+                node_reference[node->output(0)] -= 1;
+
+                blob_names.erase(node->output(0));
+
+                node->clear_output();
+                node->add_output(node3->output(0));
+
+                reduced_node_count += 1;
+                i += 1;
+            }
+        }
+    }
+
     for (int i = 0; i < node_count; i++)
     {
         onnx::NodeProto* node = mutable_graph->mutable_node(i);
@@ -1969,7 +2062,7 @@ static void fuse_bilstm(onnx::GraphProto* mutable_graph, std::map<std::string, o
 
             onnx::NodeProto* node2 = mutable_graph->mutable_node(i + 1);
 
-            if (node2->op_type() != "LSTM")
+            if (node2->op_type() != "LSTM" || node->op_type() == "GRU" || node->op_type() == "RNN")
                 continue;
 
             if (node2->input(0) != node->output(0))
@@ -2124,7 +2217,7 @@ int main(int argc, char** argv)
     fuse_pixelshuffle(mutable_graph, weights, node_reference, blob_names, reduced_node_count);
     fuse_reorg(mutable_graph, weights, node_reference, blob_names, reduced_node_count);
     fuse_expand_broadcast(mutable_graph, weights, node_reference, blob_names, reduced_node_count);
-    fuse_bilstm(mutable_graph, weights, node_reference, blob_names, reduced_node_count);
+    fuse_lstm_gru_rnn(mutable_graph, weights, node_reference, blob_names, reduced_node_count);
 
     // reduce common const weight node_reference
     for (int i = 0; i < node_count; i++)
@@ -2195,6 +2288,13 @@ int main(int argc, char** argv)
                 node_reference[node.input(2)] -= 1;
             }
         }
+        else if (op == "GRU")
+        {
+            for (int j = 1; j < node.input_size(); j++)
+            {
+                node_reference[node.input(j)] -= 1;
+            }
+        }
         else if (op == "InstanceNormalization")
         {
             node_reference[node.input(1)] -= 1;
@@ -2251,6 +2351,13 @@ int main(int argc, char** argv)
                 }
             }
         }
+        else if (op == "RNN")
+        {
+            for (int j = 1; j < node.input_size(); j++)
+            {
+                node_reference[node.input(j)] -= 1;
+            }
+        }
         else if (op == "Slice")
         {
             if (node.input_size() >= 2)