Abstract: In order to supervise the programming construction and the operating management of a municipal wastewater treatment plant(WWTP),the fuzzy matter-element model based on entropy weight of an index was used as the evaluation method to achieve the comprehensive evaluation and analysis on operation effect and its influencing factors of 8 WWTPs located in a city of North China.The primary characteristic of the method was that the weight value of an evaluation index could be objectively assigned and calculated based on actual operational data of a WWTP,avoiding subjective interferences and the experience restriction of a researcher.The evaluation result could reflect operation circumstances of a WWTP practically and objectively.The results showed that the operation effect of WWTP with A/A/O process was generally good,especially the removal efficiencies of nitrogen and phosphorus were better than other processes.TN removal rate and the productive quantity of the excess sludge cake were identified as important factors influenced the operation effect.So the operation level of WWTP could be approached mainly by increasing the TN removal rate and decreasing the excess sludge cake quantity.