Abstract: Evacuation strategies under different fire scenarios in a long urban underground traffic tunnel were evaluated by numerical methods in this paper. The available safety egress time under no ventilation condition and the required safety egress time were obtained. The results show that the required safety egress time in most scenarios are longer than the available safety egress time except in the scenarios where the fire happens near the tunnel exit portal. This might be dangerous for people who cannot evacuate safely. The smoke control system must be run in time for assuring the safety evacuation of the people at the upstream of the fire. For the scenarios near the exits of the tunnel, special measures should be taken to make the cars at the downstream of the fire drive out instantly as the smoke ventilation system is in operation.