In the view of the problem of rail traffic in wireless mesh network channel switching, puts forward a channel switching strategy based on selective scanning. Reduces the detection delay by minimizing the number of channel scanning, analyses theoretically the selective channel scanning and full channel scanning switching detection delay, and simulates the switching scene through the OPNET. The experimental results show that compared with the full channel scanning algorithm, the selective channel scanning switching strategy can effectively improve the performance of the wireless MESH network by reducing the switching delay of about 130 ms.