Based on real background of public security at home and abroad as well as the foregone researches by experts,this paper sets up comprehensive evaluation index system for public security,determines the weight of each indicator by skillfully using FAHP and grey comprehensive evaluation method,constructs public security evaluation grades and comprehensive evaluation model for public security,and makes comprehensive evaluation on public security by using comments set to calculate the grade of each indicator in the model and the size of grey association degree form the comments.