Microgird is now conductive to solve the problems of energy storage and environment pollution as a comprehensive energy system, which has a bright future for application. A Mixed Inter Programming (MILP) model is presented in this paper with the modeling purpose of operating cost and unit power purchase price, which considers the interaction among source-grid-load-storage and aims to keep the balance among multi-subject interests. Firstly, the main battery model is appropriately simplified for its important balancing role in microgrid, and the cost of battery lifetime loss is obtained through experiments. Next, the influence of battery on dispatching cost is analyzed based on MILP model compared with that of new energy of different utilization factors. The system benefits of proposed model are verified by analyzing the case in 10th EMCM, the simulation result demonstrates that the proposed model can improve utilization rate of resources, reduce operating cost and increase comprehensive benefits. This work is supported by National Natural Science Foundation of China (No. 51277134).