The invention discloses an optimal control method and device for a power distribution network. The method comprises the following steps that: on the basis of the first parameter data of a target powerdistribution network, dividing a power distribution area corresponding to the target power distribution network; on the basis of the second parameter data of the target power distribution network, determining a regulation and control instruction corresponding to each preset area; and on the basis of the regulation and control instruction corresponding to each preset area, carrying out regulationprocessing on the decision variable of target equipment in the preset area. By use of the method, the problems of single control means, poor flexibility and low equipment resource use ratio of the power distribution grid in the prior art can be solved.