Abstract:Welds in structures are often subjected to both axial and tangential loads. The mechanical properties of welds in a single direction cannot reflect the real service condition. Therefore， this study compared the tensile shear and peel mechanical properties of Conventional Friction Stir Spot Welding （CFSSW）， Probeless Friction Stir Spot Welding （PFSSW） and Swept Friction Stir Spot Welding （SFSSW） joints under the optimal parameters. Moreover， a multi-condition welds service performance evaluation method was proposed for a small all-aluminum electric vehicle. And the service performance of the three types of weld was compared. The results show that the service performance of SFSSW joints in the connection region of body side surround and top cross beam under the optimal parameters was improved by 28.97% and 48.86%， compared with CFSSW and PFSSW， respectively. Moreover， in the front longitudinal beam connected region， the three types of weld showed the highest service performance. Meanwhile， the connecting parts on the floor crossbeam and floor longitudinal beam exhibited the lowest welding service performance， and the number of welding spots needs to be increased appropriately to ensure the structure’s safety.