Abstract: With the development of new energy and smart grid, the grid-connected DG exerts growing influence on every aspect of power distribution network, which brings new challenge to power grid operation and planning, so the effective assessment of the grid-connected DG is very important. According to the influence of DG on power distribution network, a comprehensive evaluation index system of the grid-connected DG is built from such aspects as power quality, reliability, economy and environment impact. In addition, membership function is used to fuzzify score, and the combined weighting method is applied to calculate weight by combining subjective and objective weights. In the end, the comprehensive evaluation results are obtained by using the fuzzy synthetic operator. Through an example, a variety of Grid-connected DG schemes are comprehensive evaluated, which verifies the feasibility of this method.