Taking the load of a public area in metro stations as the research object, we improved the calculation method for the load of public areas in metro stations on the basis of previous studies. The data obtained from the calculation method were used as the input parameter. We utilized TRNSYS to simulate the hourly cooling load of the public area of the metro station. The TRNSYS model was verified with an actual measurement result during summer of a metro station with the PSD in South China. We used the model to analyze the factors that have a significant influence on the load to tap the energy-saving potential of the station. When the fresh air valve was closed and the control temperature of the station was increased, the load in the public area of the station could be reduced by 68% and 42%, respectively. It is hoped that this research will provide guidance for metro HVAC system design, operation, and energy management.