Abstract: Based on disadvantage analysis of existing passenger flow statistical method, the method of passengers load detection through collecting the pressure of four air springs of the vehicle was put forward. By conversing a three-way valve and extracting the obligating signal of BCU control, the signal of air spring pressure was obtained. The online test was taken through collecting waveform, extracting data, converting trainload and analyzing the results, the number of passengers within the testing period was calculated which could meet the requirements of load calculation and safety analysis.