The 6061-T651 aluminum alloy samples are treated by laser shock processing (LSP) with high power and short pulse NdYAG laser, and then are kept warm at 200 ℃, 300 ℃, 400 ℃ and 500 ℃ respectively. The effects of 6061-T651 aluminum alloy on mechanical properties after LSP are analyzed from residual stress, micro-hardness and microstructure during elevated temperature. The results indicate that the strengthening effect of 6061-T651 aluminum alloy by LSP at elevated temperature is obvious. The maximum residual stress of specimens are tested in subsurface at 200 ℃ and 400 ℃. At the same time, the higher the temperature, the faster the residual stress releases. The hardening layer depth of 6061-T651 aluminum alloy is about 0.3 mm. The primary cause of improving micro-hardness is grain size and strengthening phase, and the pitting resistance of 6061-T651 aluminum alloy is improved obviously by the big and discontinuous precipitated phase.