Abstract: This study was carried out to improve the thermal conservation of greenhouses by installing fixed screens under the condition of moveable screen. The results of the experiment indicated that this measure was remarkable. In the middle of March, fixed screens using mulch as materials can increase the temperature of 1.0～3.1℃, the average temperature from each spot 1.4℃, and the minimum night temperature 1.4℃. Particularly at the case of low temperature period, the function of the fixed screens was more efficient. Heat in the fixed screens was transferred toward south and to the borders. As the cost of fixed screens with mulch material is low and the operation is easy, the effect is excellent. However, it has the disadvantage of reducing the light intensity in greenhouses.