Abstract: The pneumatic load generated by a train passing through tunnels at high speed is closely related to the fa? tigue life of the overall metal structure of the train, the windows, the windshields and the air conditioning and ventilation units, thus making it one of the important factor to consider in guaranteeing the safety of the train. This analysis uses a one-dimensional compressible non-constant nonequivalent entropy flow model and the generalized Riemann variable characteristic line method to investigate the effects of the train ′ s airtight performance, train length,blockage ratio and tunnel length on the pneumatic load of the train body during train operation (400 km/h) in a highspeed railroad tunnel. The results show that the better the airtight performance of the train is, and the longer the train formation and the larger the blockage ratio are, the greater the amplitude and the longer the action time of the pneumatic load will be. Also, with the increase of the tunnel length, the pneumatic load amplitude shows a trend of increasing before decreasing with an "unfavorable tunnel length", and the pneumatic load amplitude of the train body can be conservatively estimated by calculating the pressure amplitude of the train body ′s surface.