Abstract: 6061 aluminum alloy was repaired by laser melting deposition of AlSi10Mg aluminum alloy coating. The effects of laser power (1 200–2 000 W) and scanning speed (8–16 mm · s⁻¹) on the relative density of the repair layer were investigated, and the phase composition, microstructure, residual stress, microhardness and tensile properties of the repair layer with the best densification were analyzed. The results show that with the increase of laser power or scanning speed, the relative density of the AlSi10Mg aluminum alloy repaired layer basically first increased and then decreased, and was the highest when the laser power was 1 800 W and the scanning speed was 12 mm · s⁻¹, which was 99.57%. The repair layer contained coarse dendritic region and fine dendritic region, and the microstructure was cellular eutectic, which consisted of columnar dendrite and equiaxed dendrite. The eutectic silicon phase was distributed in the α-Al phase matrix, and there was also a small amount of Mg₂Si precipitated phase. The microhardness of the repair layer was in the range of 96–136 HV, which was higher than that of the 6061 aluminum alloy matrix, and the residual tensile stress was in the range of 83–116 MPa. The tensile fracture position of the repair sample was in the repair area, the tensile strength reached 98.4% of that of the matrix, and the percentage elongation after fracture was comparable with that of the matrix. There were dimples, cleavage planes and holes on the fracture surface, and the fracture mechanism was tough-brittle mixed fracture.