The thermodynamic performance of a novel combined heating and power system integrated with biomass partial gasification and ground source heat pump has been investigated previously, while system performances are greatly dependent on system component capacity and operation strategy. In this paper, a multi-objective optimization model of proposed integration system is presented, which considers the energetic, economic and environmental performances. The optimal parameters are mainly consists of three parts: the rated power of power generation unit, carbon conversion ratio and the temperature of warm water. Genetic algorithm is adopted to optimize the component capacity and operation strategy of proposed system. In order to demonstrate the optimal model, a case study is adopted. The optimal results show that the primary energy saving ratio, annual total cost saving ratio, carbon dioxide emission reduction ratio and performance indicator are 7.61%, 23.62%, 66.52%, 32.58%, respectively. In addition, the influences of related economic factors on proposed system performances are also analyzed. Finally, the research shows that the multi-objective optimization model provides a new way for the optimization design of the integration system.