Selective laser melting (SLM) is significantly influenced by the matching of process parameters, such as laser power, scanning speed, and laser overlap ratio, which directly affect the forming quality. This paper established the finite element method to simulate multi-layer multichannel for SLM process parameters, especially laser overlap rate, including thermal coupling model correction, and laser parameters setting, scanning path design. The relationship between the temperature field and thermal stress accumulation was obtained. According to the statistical analysis, laser overlap rate from 20% to 30% range is advisable. Then, the simulation results were verified by experimental samples with the same size. The four groups of samples respectively reflect the influence of different parameter changes on the residual stress, which verifies the effectiveness and scalability of the simulation. Finally, the actual laser overlap rate was discussed and the action value of the designed laser overlap rate was modified.