In order to solute the problems of selection and improvement of parts when the product family architecture to adapt to the diverse needs, the selection method of parts in product family evolution was proposed herein. The Commonality (C) of parts, and the Sensitivity (S) of the parts performance and the Matching degree of demand characteristics for parts were analyzed respectively. The parts CSM couple space model in product family was defined and established, the clustering method based on fuzzy Cmeans (FCM) for parts was used in CSM coupling space of parts and the equivalent distance of the cluster centers were calculated. On this basis, the levels of all parts were determined and then the parts selection domains meeting the threshold were determined and further validated the parts of improvement object. Finally, the wheel loaders manipulator product family as an example was employed to demonstrate the feasibility of the proposed method.