During the melting and solidification process, volume shrinkage occurs in the corresponding parts of the selected laser melted powder layer, which further affects the temperature distribution of the powder layer. It is urgent to conduct corresponding analysis and research on the influencing factors of its process parameters. This paper is based on the finite element method and adopts the moving mesh technology to establish an equivalent model for the shrinkage of the selected laser melting powder layer. The influence of shrinkage on the simulated temperature distribution of the selected laser melting is analyzed, and the temperature field distribution of the powder layer under different laser powers and scanning speeds is further analyzed, verifying the feasibility of the model. The results show that by using an appropriate grid movement speed, the powder layer shrinkage of selected laser melting and forming can be effectively simulated under different laser powers and scanning speeds. The shrinkage model can better simulate the temperature field distribution of selected laser melting. This method provides a new approach for achieving equivalent simulation of volume shrinkage of powder layer during selective laser melting and forming process.