In recent years, highway tunnel fire accidents have occurred from time to time. Because of its closeness and narrow length, once a fire occurs, it is more likely to cause mass casualties. In order to explore the evacuation safety of highway tunnel and the strategy to improve its evacuation efficiency, Nanjing Fugui mountain double line highway tunnel is selected as the research object. The simulation model is established by using pyrosim, and FDS is used to carry out the numerical simulation of fire under typical working conditions (fire source power is 3MW, 15MW, 20MW and 30MW respectively). The temperature, CO concentration and visibility in the tunnel are analyzed to determine the available safe evacuation time. The required safe evacuation time is obtained through the evacuation simulation by Pathfinder, and then the judgment and evacuation strategy optimization verification are carried out according to the safe evacuation criteria. The results show that: The greater the power of the fire source, the shorter the time to reach the dangerous state, and the fire conditions of 15MW and above can not meet the safety evacuation requirements, indicating that the safety evacuation requirements are not met in case of large fire. The safe evacuation can be ensured by increasing the longitudinal wind speed, adding smoke exhaust devices and optimizing the evacuation route. The research results can provide reference for emergency evacuation of highway tunnel fire.