In this paper, the temperature field distribution of high entropy alloy (HEA) CoCrFeMnNi fabricated by selective laser melting (SLM) is numerically simulated by Ansys finite element analysis software. Considering the thermophysical parameters varying with temperature, the finite element model of selective laser melting is developed. The loading of Gaussian cone heat source is realized by inserting parametric design language into Ansys-Workbench. The influence of power and speed on the temperature field in the forming process was studied. The simulation results show that with the increase of SLM laser power and the decrease of SLM scanning speed in single-layer and multi-channel simulation, the weld pool length and width of HEA CoCrFeMnNi fabricated by SLM are increasing.