Aimed at the precision measurement during the manufacture process of antenna reflector, a measurement method based on automatic measurement technique using CAD model and data process technique was proposed. Through the planning of measuring points and aligning of workpiece with CAD model, the complete measuring data of reflector were acquired automatically. The optimum matching between the measuring data and the CAD model was achieved by the optimization algorithm, then the surface accuracy of the reflector was precisely evaluated. The transformation matrix was also obtained. Finally, the surface deviation trend of the antenna reflector was expressed by the deviation vector graph, and the datum was corrected by using the transformation matrix, which ensured the surface accuracy and machining accuracy of reflector. The practical application has indicated that the method could meet the measurement requirements of reflector.