The combined cooling, heating and power (CCHP) microgrid is a kind of distributed power system with the cogeneration plant as the core part, existing three kinds of energy balance, including various distributed micro-sources. The CCHP micro-grid has a lot of advantages such as high energy utilization ratio, strong power supply reliability, low environmental pollution and flexible dispatching. Models of mixed integer programming (MIP) composed by a variety of power mathematical models and constraints are established, so the system can better accord with the actual situation. Considering the economic dispatching of micro-grid, this paper simulates the optimization of typical day of each month for the minimum cost of overall system using CPLEX and the result should meet the needs of electrical-cold-heat load in this micro-grid. Simulation of optimal sizing and the optimized operation of typical daily load of different seasons can learn from the simulation results, so the powers can work economically. Meanwhile, sensitivity analysis of natural gas’s price was established to evaluate the impact on the operation of the system.