Abstract: Objective The aim is to explore the influence of robotic automatically flash grinding on microstructure and mechanical properties of friction stir welded (FSWed) joints, providing technology foundation for improving production automation of rockets storage tanks. Methods The surface morphology, microstructure and mechanical properties of aerospace 2A14 Al alloy joints with 8 mm thickness before and after grinding is compared. Results Under the optimized grinding process, FSWed flashes are removed effectively with the weld thinning of 0.3 mm, and joint surface between base metal and weld is smoothly transited. The grinding process has no effect on microstructure and mechanical properties of 2A14 Al alloy’s FSWed joints. The ultimate tensile stress and final elongation of the joints after grinding are 351 MPa and 6.3% respectively. Conclusion The surface morphology and mechanical properties of the joints after automatically grinding meets the demand for aerospace production of aluminum alloy plate with medium thickness.