Machine parts in aircraft parts on the proportion gradually increased. The machining allowance of the traditional derivation method of blank size, shape part is partly insufficient or too large, resulting in scrap and waste phenomenon of rough machining. In this case, a optimization technology of parts based on laser scanning optimization design of blank is proposed, through fitting the blank point cloud and CAD model, machining allowance on each processing surface of blank parts is solved. Then the key point of the technology is studied. The machinability evaluation and optimization design of blank parts is completed combined with the part of a certain type of aircraft, and related applications have achieved good economic benefits.