In order to solve the problem that it is difficult for traditional measuring equipment to accurately measure the combined block, a digital measuring method of blade die based on CMM is proposed. The theoretical values and vector directions of the points are automatically acquired by PC-DIMS measurement software. The coordinate system is established by iteration method. The corresponding scanning trajectory generation mode is selected, and the appropriate scanning density is set to measure the blade die, and the results are compensated in three dimensions. Using this method, the profile measurement experiment is carried out, the profile deviation diagram of blade die is drawn, and the uncertainty of measurement is evaluated. Experiments show that this method has good accuracy and high automation. It can accurately reflect the wear situation of blade die in the trial production and use stages. It provides an important reference for the repairing and maintenance of the die.