With the continuous advancement of new power reforms and the rapid development of microgrids and multiple loads, how to ensure the comprehensive benefits of grid companies′ investment in distribution networks is the key to the comprehensive background of policies and technologies. Aiming at this problem, this paper comprehensively considers the impact of micro-grid and multi-load on the investment of distribution network, and constructs a distribution network-input benefit evaluation index system. Secondly, it combines the influence of micro-grid and multi-load on the purchase and sale of electricity. The input-output model of the distribution network after the new power reform. Finally, the evaluation of the distribution network investment and the optimization of the distribution network planning project are proposed by the scoring method and the preferred method. The scoring method uses the analytic hierarchy process and the entropy weight method to determine the synthesis. The weighting and optimization method uses the improved gray correlation method for data analysis. The practical examples verify the feasibility and effectiveness of the proposed evaluation system.