The present study employs numerical simulation to investigate the transportation of fire smoke within the underground powerhouse of a Pumped Storage Power Station. The obtained results reveal the spatial variation of fire smoke under the smoke exhaust effect inside the facility. For an 8 MW fire occurring on the generator, busbar, and turbine layer floors of the main powerhouse, recommended evacuation times are 86 seconds, 242 seconds, and 298 seconds respectively when utilizing a mechanical exhaust capacity of 85000 m³/h. In case three simultaneous fires occur at these three floor levels, the evacuation time is reduced to 45 seconds. Comparatively, when compared to situations without mechanical smoke exhaust systems, our simulations indicate that escape times for different fire scenarios were extended by only 6 seconds and 91 seconds respectively. These findings underscore the urgent need for optimizing the mechanical smoke exhaust system in order to provide valuable time for personnel evacuation during fire incidents.