Abstract: To improve the efficiency of fixture design for automobile body welding automatic production line, a hierarchical case based reasoning method was presented based on basic element model. The welding feature model, consisting of position feature, shape feature and assembly feature, was introduced by analyzing various features of fixture design. Expression and storage method for fixture design knowledge based on basic element model was established, and then the welding station information model was formed based on knowledge reuse. A case, sharing the most similar welding station information, was obtained by calculating the similarity in three stages. Finally, the method was proved to be highly effective in application to the station of inner skin reinforcing plate assembly.