The utility model provides a self-adaption clamping tool for blade machining. The self-adaption clamping tool for the blade machining only conducts unstressed clamping and does not locate blades. Positioning of a blade in a clamp is finished in advance by a positioning clamp, and a control point of a blade body serves as a positioning point when the blade is positioned. A suitable clamping angle can be found by means of a spherical surface juncture, small clearance fit is is applied to an inner hole of an outer conical sleeve and the spherical surface juncture, the outer conical surface of the outer conical sleeve is contacted with an inner conical surface of an outer shell, the outer shell axially moves so that the outer conical sleeve is made to generate radial clamping force to clamp the spherical surface juncture tightly, the end portion of the blade is fixed on an outer exposed end surface of the spherical surface juncture, and clamping of the end portion of the blade can be achieved finally. Due to the fact that the outer shell is not directly contacted with a machine tool, the outer conical sleeve does not generate axial movement in the whole clamping process, only the outer shell moves relative to the outer conical sleeve so as to generate the radial clamping force to clamp the spherical surface tightly without generation of axial frictional force on the spherical surface, and the inner portion of the blade can not generate clamping force due to the fact that the clamping standard of two ends of the blade deviates when the blade body of the blade, the intake side of the blade and the exhaust side of the blade are machined.