The invention discloses a method for generating a spiral grinding tool locus for a blade, which can be used for grinding the blade body region of the blade and realizing grinding and polishing treatment after milling on a blade surface. The method comprises the following steps of: unfolding combined curved surfaces constituting the blade surface; parameterizing boundary lines which are shared by adjacent combined curved surfaces and are taken as control curves with a geometric method; equally dividing the control curves according to the number of turns of a spiral line to obtain middle control points of the control curves; performing parameter interpolation between the middle control points of two control curves owned by any single blade curved surface serving as two end points of a spiral curve locus to obtain a middle initial tool contact; and increasing points between the two points with a dichotomy method till a tool locus meeting the requirement of processing accuracy is generated. According to the method, the generated tool locus is smooth and continuous, cutter relieving is avoided in the grinding process, and transition regions among the combined curved surfaces does not swing greatly; and the method is suitable for grinding and digital control processing of combined blade curved surfaces.