Based on a multi-functional office building model,the most unfavorable fire scenario was simulated.According to fire smoke emergency critical value,a hybrid field-network model was established to simulate the fire smoke flow properties in building and the available safe egress time(ASET)was obtained.The required safe egress time(RSET)was calculated by the evacuation simulate system developed independently by Chongqing University.The occupant safety evacuation in building fire is evaluated through a comparative study of the RSET and the ASET,and measures are proposed about the safety evacuation.