A type of fresh air system integrated with shading photovoltaic is researched. In summer, photovoltaic panel is used for shading and electricity generation. In winter, this system can generate power and heat fresh air by extra thermal energy of PV panel. By using class region method, a photovoltaic and photo-thermal conversion model is established to simulate the performance of the fresh air system, and the system model is validated by experimental data. On this basis, the fresh air volume of the fresh air system integrated with shading photovoltaic is optimized. The results show that the photovoltaic power generation efficiency, the heat gain of the fresh air and the heating efficiency increase, while temperature rise of fresh air and outlet temperature of fresh air reduce with the increase of the fresh air volume, and the power generation efficiency and heat collection efficiency grow with the increase of solar radiation intensity. In this paper, the fresh air system integrated with shading photovoltaic has functions of electricity generation, shading and fresh air heating, and provides a new method for building energy saving.