Abstract: Active distribution network is an effective approach to solutions such as the high-penetration of intermittent renewable energy, interaction between grid ,charge and discharge facilities,and also the analysis and operation of smart grid. In allusion to the planning of distributed generators,a multi-objective programming model, which takes into account the least active power loss, the best voltage level and the smallest investment cost, is established. Using the fuzzy set theory to transform the multi-objective optimization into mono-objective optimization and maximizing the overall satisfaction improves the overall performance. At the same time, the modified multi-population genetic algorithm is used to solve the model. To a certain extent, this algorithm overcomes the premature convergence caused by multi-population genetic algorithm. The 35 node power system of certain city community is checked the effectiveness of the model and algorithm.