Passenger’s comfort degree is reduced due to the pressure fluctuation in the car when the train frequently passes the intermediate ventilation shafts and tunnel portals Passenger’s comfort degree control standards for Metro trains and highspeed trains developed in foreign countries and related studies made in China are summarized A model is established by means of SES 41 Metro environment simulation software, and the fluctuation of the pressure at the train head and the passenger’s comfort degree when the train passes tunnel portals and intermediate ventilation shafts under the condition of different train speeds, different tunnel crosssection diameters and different crosssection changing part lengths are calculated and analyzed In the end, some aerodynamic effect mitigation measures are proposed