Abstract: In order to reduce the impact of pressure fluctuation caused by the high-speed train passing through a tunnel on the train operation, the pressure wave characteristics of a high-speed train passing through a tunnel with a communication channel are studied based on train aerodynamics. A numerical simulation model for a high-speed train composed of three cars was established. Based on a three-dimensional, unsteady, compressible Navier-Stokes equation and k-ε two-equation turbulence model and slip grid technology, the aerodynamic characteristics of a high-speed train passing through a tunnel with a connected aisle were numerically simulated. The results shown that: the aerodynamic characteristics of the train passing through a tunnel with a connected aisle were much better than that passing through a tunnel without a connected aisle; the connected aisle had more obvious effect on the initial pressure rise and fall, and the suppression of the expansion wave was more prominent; the higher the train speed is, the larger the channel area is, and the more obvious the pressure wave falls back; the setting of the contact channel makes the pressure wave waveform show a local jagged shape. A fast formula for calculating the pressure peak of a train passing through a tunnel is also proposed.