The numerical simulation of three-dimensional flattened laser shocking of 2024 aluminum alloy is conducted with the finite element method, and the simulation results are consistent with the experimental results obtained from literatures. The influences of different process parameters on the residual stress distribution in materials are studied. The results show that, when the spot size increases, the residual stress of materials increases while the change gradient of the surface residual stress decreases. When the shocking times increase, the residual stress increases and tends to saturate. When the overlapping rate is 10%, the change gradient of the surface residual stress is relatively small. When the overlapping rate increases, the residual stress along the depth direction increases but its increasing amplitude is small.