The on-board diagnosis network is the nervous system of high-speed Maglev trains, connecting all controller, sensors, and corresponding devices to realize the information acquisition and control. In order to study the on-board diagnosis network’s security and reliability, a simulation model for the on-board diagnosis network of high-speed Maglev trains with the optimal network engineering tool (OPNET) was built to analyze the network’s performance, such as response error and bit error rate on the network load, throughput, and node-state response. The simulation model was verified with an actual on-board diagnosis network structure. The results show that the model results obtained are in good agreement with actual system performance and can be used to achieve actual communication network optimization and control algorithms.