In order to improve the resource allocation ability of grid enterprises in the development of distribution network，and to clarify the investment direction and management focus，an input － output benefit evaluation system for distribution network is designed based on relevance relation． For this purpose，taking thedistribution network investment management system of power grid enterprises and the development strategy as the outline，the key input resources and output data of distribution network are sorted out by voltage levels，and the key input indicators and key output indicators are distinguished using key success factor decomposition method． Furthermore，the design ideas of distribution network input and output efficiency indicators are clarified． Considering fully the relationship between input and output of distribution network，including seven first － level indicators such as the contribution of unit investment to the improvement of power supply quality etc，an input － output benefit evaluation system for distribution network is designed based on relevance relation，which provides a theoretical basis for power grid enterprises to clarify the investment direction and management focus，and enhances the value － added and preservation ability of state － owned assets．