To improve the defects of the strengthened layer after aluminum alloy laser cladding and enrich the basic theory of the formation mechanism and preventive measures of laser cladding cracks on the surface of aluminum alloy. In this work, the optimization of the laser cladding process parameters and the rare-earth modification were combined. To provide a reference for the optimization of the process parameters of laser cladding of aluminum alloy, the temperature field and stress field of the process of preparing Ni60 alloy strengthened layer by laser cladding on the surface of 6063 aluminum alloy were simulated by ANSYS 14.0 finite element analysis software, and the process parameters were optimized through experiments. Using optimized optimal process parameters to cladding Ni60+Y2O3 alloy powder on the surface of 6063 aluminum alloy, studied the influence of different rare earth content on the strengthened layer, obtained the best rare earth content, discussed the mechanism of laser cladding crack formation and prevention and modified measures. After optimizing the laser cladding process parameters through finite element simulation, aluminum alloy strengthened layers with different rare earth contents were prepared. When there no rare earth was added, the surface cross-sectional morphology of the Ni60 strengthened layer was the worst, and a large number of pores and cracks appear in the strengthened layer. When the rare earth content was less than 4%, the amount of pores and cracks in the strengthened layer decreases with the increase of the rare earth content. When the rare earth content is 4%~5%, the thickness of the strengthened layer reaches 1000 μm, and the cross-sectional morphology had no obvious pores or cracks. The cross-sectional morphology was better. When the content of rare earth exceeded 5%, the pores and cracking phenomenon increase. Combined with the residual stress simulation analysis, the formation mechanism of the aluminum alloy laser cladding crack strengthened layer cracking was solidification crack and liquefaction crack. Combining finite element numerical simulation to optimize the process parameters of laser cladding and rare earth control modification can well improve the problem of cracking of the laser strengthened layer on the surface of aluminum alloy.