The infiltration air volume of platform screen doors (PSD) is an important factor affecting the cooling load of subway station. This paper proposes a calculation model of infiltration air volume. Through the analysis of test wind speed, the characteristics of infiltration air volume of PSD are studied by location and stage. Then, through the analysis of train operation factors, a calculation method of total infiltration air volume of PSD is established, The results show that: 1) the infiltration wind speed of PSD at different positions is different. Along the running direction of the train, the infiltration wind speed and air volume of PSD in a single cycle decrease with the change of door position. 2) There are also differences in the infiltration air volume of PSD in different stages. The total infiltration air volume in a single cycle in the train stopping stage is the largest, which is about 10 times that in the station. 3) The range of infiltration air volume of single cycle PSD is given, which provides a basis for the calculation of total infiltration air volume,and the corresponding calculation model is proposed, which can calculate the whole day air volume of PSD penetration of subway station.