Based on the three-dimensional constant incompressible viscous flow field NS and the equation turbu- lence model, the finite-volume numerical simulation method was used to analyze and calculate the local flow field structure and pressure wave distribution of a 350 km/h high-speed train operating on the long-haul lines and extra long double-track railway tunnels. The study finds that the distribution structure of the air flow field is complex and irregular. As for the train, the static pressure on the side of the train approaching the tunnel is greater than the static pressure on the side near the tunnel center line and the pressure fluctuation on the side of the front windward side. The phenomenon is more obvious, and the static pressure on both sides gradually de- creases along the length of the train; As for the tunnel, the static pressure on the side of the tunnel with the train running and on the side without the train gradually increases along the length of the train, then it drops at the head of the train and gradually descends at the rear of the lee side train. The sudden increase reaches a maxi- mum value, then gradually decreases and tends to be stable. The static pressure on the inner profile of the train is located near the driver's cab of the train head along the length of the train. The phenomenon of pressure fluc- tuation is obvious, and the pressure fluctuation on the windward side is more obvious. The leeward side is more prominent, and there is almost no pressure fluctuation in the no-vehicle side, and the profile static pressure dis- tribution is gradually stable along the bottom of the tunnel toward the top of the tunnel.