Abstract: Using moving model tests, the pressure distribution and variation inside a tunnel and on a Platform Screen Door (PSD) have been investigated for the cases of a train passing the tunnel, passing the station and tracing. The scale ratio of the standard A⁺ subway train model is 1:20. It is found that a pressure wave is generated when the train is passing the shaft of the tunnel, which is similar to the situation when a train is entering a tunnel except for the smaller extreme pressure value. For the case of a train passing a station, the pressure on the PSD is dominated by the pressure wave transfering through the tunnel; when the train reaches the station, this pressure experiences another extreme value, and then shifts to a negative extreme value immediately when the train's head passes the PSD. These extreme pressures determine the strength design criteria for the PSD. For the train tracing case, the pressure on the PSD reaches its extreme value caused by the pressure wave when the coming train is still at a distance from the station. Then, this pressure decreases slightly and keeps approximately constant for a period. This lateral pressure is the reason why the PSD cannot open or close properly.