There are platform screen doors in the underground stations of Kaohsiung mass rapid transit system. So the design of tunnel ventilation system is different from the system without platform screen doors. Under normal or congested condition the tunnel ventilation system could keep the temperature in tunnel low enough to facilitate train’s air conditioner providing a comfortable environment for the passenger. While there are fire condition, the train couldn’t keep running to the next station and stops in the tunnel. The passengers must evacuate via track bed to the next station. In this circumstance, tunnel ventilation system must establish a path free of smoke for the evacuee. Kaohsiung mass rapid transit system had integrated all the facilities and measures, for example, reducing fire agents and using low fire propagation or fire retarding materials to prevent fire occurrence and spread, developing rescue and evacuation installations to help passengers escape, setting up communication system for employee and fireman to contact each other, also supporting by all kinds of procedure to establish a complete hierarchy, against fire disaster in the tunnel to ensure safe for the passengers.