Al-70 Si alloy was prepared by multi-laser cladding on 1050 aluminium alloy with LWS-1000-Nd:YAG laser. The microstructure and mechanical properties of Al-70 Si cladding layer were investigated. The effect of heat treatment on microstructure and properties of cladding layer were explored. The results show that Al-70 Si alloy is successfully fabricated by laser processing technology. In the cladding layer,the morphology of silicon particles are cha-racterized by round spherical shape,long strip shape and five-star petal shape respectively. The average hardness of the cladding layer is 250 HV,the tensile strength is 85 MPa,and the wear resistance of the substrate is obviously imp-roved. After heat treatment at 500 ℃ for up to 4 h,because of the reduction of silicon particle size and more rounded silicon particles,the maximum value of cross-section har-dness is improved by 50 HV and the thermal conductivity also increases accordingly.