With the exhaustion of fossil energy, distributed energy system has become a research hotspot.This paper，which bases on isolated community load ，builds a distributed energy system powered by photovoltaic array, wind generator, diesel generator and battery based on the modeling of isolated cell loads, and proposes a multi-objective optimization case that takes into account net present value cost, environmental penalty and renewable energy utilization hours simultaneously.The optimization variable was wind generator type, wind generator number, photovoltaic array capacity, diesel generator type, diesel generator number and battery group. A non-dominant sorting genetic algorithm with elite strategy was used to solve the optimization model.The relationship between distributed energy subsystem is obtained by analyzing component life sensitivity.Moreover, taking a small plot microgrid as an example was studied and compared with HOMER Pro''s calculation results. Finally, the optimal equipment capacity of the small plot microgrid was obtained. The results showed that the proposed optimization design method was reasonable and feasible, providing a case for engineering design.