The invention provides a method and system for researching power distribution network operation mode optimization. The method comprises steps: a current operation mode of a power distribution network is determined, and historical data corresponding to the current operation mode of the power distribution network is obtained; an object function and constraint conditions of power distribution network operation optimization are constructed, corresponding flexible parameters are introduced, and flexible description of the constructed object function and constraint conditions is carried out respectively; based on the object function and the constraint conditions after flexible processing, a multidimensional flexible integrated optimization model of power distribution network operation is formed, the obtained historical data is introduced into the multidimensional flexible integrated optimization model for solving, and the optimal desired value of the current operation mode of the power distribution network is obtained. The constructed optimal model of power distribution network operation is subjected to border flexibility, power distribution network operation structure and parameter change is adapted flexibly, the research flexibility is raised, research is carried out from many aspects and thus research is comprehensive.