In order to improve the detection accuracy of road network traffic incidents and reduce the false alarm rate, a real-time automatic detection method of road network traffic incidents based on Graph Spatial-Temporal Pattern Learning Network (GSTPL) is proposed. Firstly, the traffic incident detection problem in the road network is abstracted into a graph structure anomaly detection task; a traffic spatial-temporal fusion graph representation method is designed to filter the road network graph node with strong spatial-temporal dependence and same pattern regularity as the input. Then, the graph spatial-temporal convolution and graph embedding layer are introduced to extract the spatial-temporal pattern features, and the multi-component input and fusion prediction structure are constructed to fuse traffic pattern rules in different time dimensions, and realize stable forecasts of graph node parameters. An abnormal state evaluation method is designed, and the final incident detection result is given by learning of the prediction error distribution and combining with the current detection data. Two real road networks datasets were used for validation experiments, and the proposed algorithm was compared with several typical traffic incident detection algorithms. The comparison results show that the proposed GSTPL has higher detection accuracy, lower false alarm rate and shorter average detection time. When the acceptable false positive rate is 5% and 10%, the detection rate of traffic incidents can reach more than 91% and 96% respectively.