Abstract: Aiming at the key problem for measuring of coordinate measuring machine (CMM) of the aeroengine blade surface data processing, a kind of error separation method for blade surface was proposed. The contour measurement method was used for measuring the blade, and calculation method of blade surface tolerance evaluation index, principles and procedures of the error separation techniques were given. In order to separate the curve profile error of blade surface, torsion error and position error which are from the comprehensive error to determine the blades whether were qualified, the minimum zone method was used for matching the measurement points and the theoretical cross section contour corresponding points in the data processing The matching objective function and solving steps were established and DFP variable dimension algorithm was used to solve it. The influence of establishing coordinate system error was eliminated through the second match.Finally, the examples showed the method was valid and practical.