To investigate the cooling load variation induced by unorganized infiltration airflow in platform screen door metro stations, field measurements and numerical simulations are conducted at a non-transfer underground platform screen door metro station in Shanghai. A simplified simulation model for unorganized infiltration airflow is developed and validated using on-site infiltration airflow data collected at platform screen doors and station entrances/exits during train arrival and departure cycles. The dynamic variation patterns of unorganized infiltration airflow are systematically analyzed, and the validated model is employed to calculate real-time infiltration load profiles for two typical scenarios of weekdays and weekends. The results show that the infiltration air load is increased during the peak passenger flow period, and the maximum infiltration air loads on weekdays and weekends are 29.8% and 30.8%, respectively.