The microstructure,mechanical properties and fatigue properties of the welded joints of 6005A-T6 aluminum alloy hollow profiles with welding grooves and surfaces sub-jected to three different grinding states are studied. The results show that the three grinding methods can obtain welded joints with good appearance. There is no significant difference in the microstructures of the weld,fusion zone and heat affected zone in the welded joints with three grinding states. The tensile properties of three kinds of welded joints are basically the same,the differences in the average tensile strength and average elongation after breaking are slight,and all three joints have good bending performance. The hardness distribution of three kinds of joints is similar. S-N curve fitting fatigue limit is the same,all are 89 MPa. Three different grinding methods before welding have little effect on the microstructure,mechanical properties and fatigue properties of the welded joints of 6005A-T6 aluminum alloy hollow profiles.