Evacuation efficiency of public buildings are closely related to their space structures. However, there is lacking of correlating analysis methods of both of them, which lead to the ignoring of evacuation efficiency contribution not able to support the space structure design of public buildings. In this paper, we proposed a concept of hierarchical organization map of public buildings, then proposed a quantitative measurement method of evacuation efficiency contribution for space structure combination models of public building. This paper developed an prototype system to implement this method, and testing of 7 building design plans were shown to validity the proposed method. This method can make up the lacking of quantitative measurement approach of evacuation efficiency, which can provide scientific reference for architecture design in order to meet the requirements of evacuation performance of public buildings.