Abstract: The pretreatment technology of rapeseed extrusion for solvent extraction of oil was discussed. The experimental design based on the dimension analysis and G.Murphy theorem corrected by Jiang Yiyuan. The effects of extrusion parameters such as moisture content of material, temperature of barrel, rotational speed of screw, diameter and lenght of die nozzle, distance from screw end to die nozzle on the ratio of residual oil were studied . The experience formula was founded indicating the relationship between ratio of residual oil and extrusion parameters. The experiment indecates that the experience formula can predict the ratio of residual oil exactly.