Abstract: In order to solve the problem of accumulation and congestion of soil and membrane during the separation of membrane and soil, a membrane-soil separation device has been designed. In order to study the factors which affect the performance of the membrane-soil separator and determine the optimum working conditions of the membrane-soil separator, the theoretical analysis and bench test of the membrane-soil separator have been carried out. The main factors are the spacing（the distance between two adjacent hanging film nails on the same hanging film block）, the cone Angle（the cone Angle of the cone at the end of the hanging film nail） and the Velocity ratio（the ratio of the velocity of the membrane soil mixture before it enters the membrane soil separation device to the linear velocity of the conveyor belt）. The soil removal rate is taken as the evaluation index, and the three-factor three-level response surface test has been carried out for the membrane-soil separation device. By using Design-Expert data analysis software, the significance of each factor to soil removal rate has been analyzed. The results show that the three factors influence soil removal rate from big to small is velocity ratio, distance, cone angle. When the distance is 90.23 mm, the cone angle is 34.60°and the velocity ratio is 0.81, the membrane-soil separation device can complete the membrane-soil separation well.