This paper assess a power plant boiler in Yunnan based on the feature of power plant boiler. Considering some factors including man, machine and environment management, Fuzzy Comprehensive Evaluation Method was used to establish comprehensive evaluation system of power plant boiler. the weight value of each index was determined by using AHP, and the expert group was established to comprehensive evaluate of the system power plant boiler. The weighted average principle was used to get the final results of the evaluation. Studies shown that application of fuzzy comprehensive evaluation method in power plant boiler could improve the scientific and practical of safety evaluation.