Combined heating and power (CHP) microgrid is conducive to the realization of energy cascade utilization and meeti the users' needs with divers types of energy. With remarkable economic and environmental benefits, CHP microgrid is one of the potential development directions of smart grid. In this paper, a CHP microgrid consists of wind turbines, photovoltaic cells, microturbines, gas-fired boilers, storage batteries, heat load and electric load was selected as research object. In order to evaluate the impact of CO 2 , CO, NO x emission on environment, the conception of gas emission plenty cost was quoted. In consideration of the stochastic nature of renewable energy units and the fluctuation of heat load and electric load, chance constrained programing was introduced to build the model, then Monte Carlo simulation based leapfrog firefly algorithm was proposed to solve the optimization model. The simulation results verified the reasonableness and effectiveness of the model and algorithm proposed.Index Terms--combined heating and power, microgrid, dynamic optimal dispatch, leapfrog firefly algorithm.