Abstract: The simulation model for thermal environment in Chinese solar greenhouse was established, in which the solar radiation, heat radiation, heat convection, heat conduction, natural ventilation and water phase transformation were described quantitatively. And the impacts on thermal environment were analyzed. According to thermodynamic law of conservation of mass and energy and heat transfer theory, a group of differential equations on thermal balance of cover, thermal balance of indoor air, thermal balance of multi-layers of north wall, thermal balance of multi-layers of soil, thermal balance of multi-layers of north roof and thermal balance of plant were built. The simulation model was developed with MATLAB procedures used to solve differential equations, and good user interface of VB, and the temperatures of different parts could be calculated. It shows that the model can accurately predict the temperature in greenhouse environment from experimental results.