The invention relates to a method for degumming crude soybean oil by an immobilized phosphatidase membrane. The method allows problems that the soybean oil degumming effect is bad because the temperature and the pH are difficult to control in present enzyme degumming methods and the cost of the present enzyme degumming methods is high to be solved. The immobilization of an enzyme is in favor of the dispersion, the recovery and the reutilization of the enzyme, so the loss of the enzyme and the repollution of the residual enzyme are reduced. The method for degumming the crude soybean oil by the immobilized phosphatidase membrane comprises the following steps: 1, preparing a composite membrane; 2, immobilizing phosphatidase; 3, carrying out early stage processing on soybean oil; 4, adding the immobilized phosphatidase to the soybean oil; and 5, stirring, and centrifuging. So the crude soybean oil is degummed by the immobilized phosphatidase membrane. By adopting the method in the invention to degum the crude soybean oil, the degumming efficiency is 20-30% higher than the degumming efficiency of the present degumming methods, and the production cost is 20-40% lower than the production cost of the present degumming methods.