Firstly the paper introduces solar modules' internal structure and its equivalent circuit. According to different shading situation output characteristic of solar modules, the problem was analyzed by equivalent circuit. Through the actual shading test, the same type of solar modules in different shading mode solar module I-V characteristics and the influence of power were measured. Finally, the shading of effects the different types of solar modules was comparative analyzed. Research results can be used as the reference of solar modules installation location.