Abstract: To decrease the effect of compression wave, the numerical simulation of a three-dimensional viscous flow induced by a high-speed train entering tunnels with a shaft was made. In the simulation, the Navier-Stokes equations, describing three-dimensional viscous, compressible, isentropic and nonstationary flows, were taken as the control equations, the cell-centered finite volume scheme for numerical integration of the Navier-Stokes equations was used for space discretization, and the preconditioned second-order accurate backward difference was adopted in time discretization. In addition, the walls and floor of a tunnel were described with wall functions. The calculated result agrees with the oversea experimental one.The research shows that the shaft can decrease air pressure in tunnels, and its section area and position have a great effect on the pressure.