The invention discloses a power distribution network optimization method and a power distribution network optimization device, wherein the power distribution network optimization method and the power distribution network optimization device relate to the technical field of a power system and settle the problems of high active network loss and low operation safety in a power distribution network. The power distribution network optimization method comprises the steps of acquiring control variables, and determining line parameters and operation data of the power distribution network according to the control variables, wherein the control variables comprise reactive power output of reactive compensation equipment, gear of a loaded voltage regulating transformer, active power output of an energy storage device, and power factor of photovoltaic power generating equipment; establishing an objective model according to the line parameters and the operation data; performing calculation by means of a non-dominated sorting genetic algorithm with an elitist strategy for obtaining a Pareto optimality solution set of the objective model, and performing calculation for obtaining a standard satisfaction which corresponds with each solution in the Pareto optimality solution set; obtaining an optimized objective model, and adjusting the control variables of the power distribution network according to the control variables which correspond with the optimized objective model. The power distribution network optimization method and the power distribution network optimization device are applied in the power distribution network.