The invention discloses a dynamic evaluation method for power supply quality of a power selling enterprise considering different user requirements under a market environment. The method comprises thefollowing steps that a three-level evaluation index system including a target layer, a criterion layer and an index layer is established from five dimensions of power quality, power supply reliability, service quality, economy and market share; according to the demand preference and perceived value of power supply quality of different groups of users, the power supply quality of power selling enterprises is evaluated subjectively; the power supply quality competitiveness of each power-selling enterprise are evaluated objectively from the system angle; according to the subjective and objectiveevaluation results, the power supply quality competitiveness of the power supply enterprises are comprehensively evaluated; the dynamic comprehensive evaluation including the horizontal benchmarking including the power supply quality competitiveness of each power selling enterprise, and the vertical benchmarking including the dynamic trend of the power selling enterprise compared with its own historical level is carried out. The method of the invention can select suitable power selling enterprises for users and encourage each power selling enterprise to improve the power supply quality and thepower quality of the whole distribution network.