The invention belonging to the technical field of energy consumption in a distribution networks particularly relates to a comprehensive evaluation method for an influence on energy consumption of a distribution network by power quality. Power quality indexes include a harmonic value, a voltage three-phase unbalance degree, a voltage deviation value and a reactive power value. Electrical parameters are collected and power quality index line loss models are established; and when two or more of the harmonic value, the voltage three-phase unbalance degree, the voltage deviation value and the reactive power value occur simultaneously, calculation is carried out to obtain a total increment of power supply line losses, so that comprehensive evaluation for an influence on energy consumption of a distribution network by the power quality is realized. According to the invention, main factors and an influence mechanism of the influence on the energy consumption of a distribution network by the power quality are systematized and models are established to quantize the influence result, so that evaluation of the influence on the energy consumption of the distribution network by one or multiple power quality indexes is realized, the energy consumption situation of the distribution network is reflected objectively and actually, and the reliable basis is provided for energy conservation and power consumption.