Simulations of solar energy diffusion among households benefit the promotional strategies plotting. In this paper, an agent-based model is built for simulating the solar energy diffusion process in residential consumer market. Selfdeveloped surveys indicate that purchase price and government policy are the most important features which impact the households' solar energy adoption behavior. Changes of residential consumer market share are investigated with various features of purchase price and government policy respectively. Random forest and partial dependence plots are used to analysis the simulation results. It is shown that purchase price does play important role in market share changes of solar energy. But government policy is more effective in solar energy diffusion process. The promotion strategies of solar energy must be enhanced if there exits policy benefits for other kinds of energy.