From the perspective of customers'different demands， a novel comprehensive power quality evaluating method is presented. First， the incomplete linguistic evaluation information is used to describe the emphasis and subjective evaluation of different technical power quality indices by different customers. And then， the linguistic evaluation information is considered as evidence to determine the customers'subjective evaluation of all observation points. Finally， all customers' subjective evaluation information is synthesized to grade the power quality of all observation points. In the synthesized processing procedure， the conflict degree exponent is defined to describe the conflict between customers， and the weights of different customers are determined based on conflict degree exponents. The proposed method not only considers different customer demands， but also embodies the evaluation opinion of most customers. The effectiveness of the proposed method is validated by case study.