Abstract: Because of a variety of power quality indicators and some of them possess fuzziness,so it is difficulty to make fuzzy synthetic evaluation for power quality has difficulty.Therefore,This paper proposes an improved Analytic Hierarchy Process(AHP),which make objective weighting about power quality indicators with comprehensive expertise and actual situation,meanwhile calculate the objective weight using the method based on the Law of Entropy.On this basis,we can calculate the comprehensive weight,which can reflect the objective facts well and compensate the lack of traditional AHP.In the meanwhile,this paper establishes their own fuzzy mode for various indicators of power quality,and then conduct grade determination in order to achieve the object of making comprehensive assessment of power quality.