Light illumination is the important factor that affects the performance of solar greenhouse. Structure(geometric shape) of solar greenhouse has a direct effect on light illumination when using the same constructing materials. The results analyzing light illumination inside three different structural solar greenhouses, i.e., single slope greenhouse, parabolic greenhouse, circle-parabolic greenhouse, show that circle-parabolic greenhouse can reduce the difference of light illumination between south and north and rise light transmissivity, but light illumination inside house is less than that outside, and the difference of light illuminations was notable. Reflecting film was covered on the back wall of greenhouse. In a word, above methods can reduce the difference of light and ameliorate illumination between south and north notably in the greenhouse, and improve the light environment still in the locations close to the back wall. This method can increase crop yield.