Abstract: Problems of total wind under pressure caused by air spring pressure rapid rise of metro vehicle braking system are introduced, and the principles of air supply system and air spring system are analyzed. AMESim, an engineering system simulation software, is used to model the air source, air spring and other main components of the vehicle braking system, and the pressure curves of how total air pressure changes as load changes under different working conditions are obtained. Based on the simulation results, corresponding suggestions are put forward for the problem of total wind under-pressure caused by the rapid increase of air spring pressure of metro vehicles.