Laser shock processing (LSP) employs high-energy laser pulses from a solid-state laser to create intense shock waves into a material, which can induce compressive residual stresses in the target surface and improve its mechanical property efficiency. Three different ablative, sacrificial coating were chosen to protect the 6061-T651 alloys from surface melting by laser pulse. This paper analyzes the effect of the paint and foil coatings on the shock wave propagation into the 6061-T651 alloys and the resulting change in mechanical properties. The depths of hardening by laser processing of 6061-T651 alloys up to 1 mm, and the surface hardness reach to 138HV. When the laser pulse energy density increase from 2.8 GW/cm2 to 3.6 GW/cm2, the surface hardness of the black paint, aluminum foil and silica acid black paint samples increase to 19, 27, 36 respectively.