The CATIA finite element analysis (FEA) process was summarized，virtual parts were used to simplify the finite element model of dooropening mechanism，and then the complicated FEA of dooropening mechanism was simplified to FEA of single part. Within the ideal range of transfer error，the results from CATIA FEA and NASTRAN were compared and analyzed. Based on stress concentration data by CATIA, a data processing method was presented for design, and a test was carried out to validate the method, which could provide some valuable references to structure designers.