In this paper, according to the characteristics of structural parts, CAPP system is constructed based on manufacturing feature of aeronautical structural parts to improve the production efficiency of aviation structural parts. Six manufacturing features are summed up according to the machining process by researching on classification of common aircraft structural parts. In the VC++6.0 environment, a coding system based on manufacturing feature is designed according to OPITZ standard. The step retrieval algorithm is designed for feature recognition about between target parts and entity library parts. The similarity of features is achieved between the target parts and the physical library parts. Taking the frame parts with 44 slots as an example, 40 Manufacturing features are automatically identified by the algorithm program. The automatic recognition rate is 91%. The result showed the feasibility and correctness of the algorithm in CAPP system.