Abstract: Due to the affection of both randomness of distributed generations and fluctuation of electricity loads the uncertainty of the active distribution network increases. In traditional power quality assessment method for distribution network, which is based on the measured value of data points, a lot of uncertain factors caused by multiple disturbance sources have not been considered. Thus, an interval quantization comprehensive assessment method, which took the uncertainty of distribution network into account and suited to deal with interval power quality indicators, was proposed. Firstly, a normalization method to process interval index data was given. Secondly, a combination weighting approach, in which the multi-expert consultation G1 was combined with the improved entropy weight method, was proposed. Thirdly, in allusion to the characteristics of interval data, an ranking method based on possibility calculation was used to rank the assessment results to make the results clear and intuitive. Finally, utilizing IEEE 33-bus distribution system for calculating example, the effectiveness and feasibility of the proposed method were verified.