In the aerospace industry, due to the increasing hardness and tensile strength of nickel-based superalloys, the traditional manufacturing methods are difficult to produce, which limits the freedom of part design and process. Selective laser melting (SLM) has great potential in this field with its additive manufacturing concept and full melting during the process. Although the dense part can be easily obtained in SLM, the residual stresses and micro-cracks in the machining process still affect the dimensional accuracy and reliability of the parts. In SLM process, rapid and complex changes of temperature and stress are observed in the vicinity of the molten pool. Understanding these changes will help to improve the quality of the process. In this work, a finite element model (FEM) is established to calculate the temperature and residual stress distribution near the weld pool during the SLM of Hastelloy X superalloy, The model uses a composite Gauss heat source to consider the influence of optical penetration depth, and implements the transformation of powder, molten pool and solid metal by changing the material properties with temperature. Comparison with the test results shows that the model can simulate the distribution of temperature field and the residual stress in SLM process well. The simulation results show that with the increase of laser power, the width, length and depth of melting pool were enlarged, the cooling rate decreases; with the increase of the scanning speed, the width and depth of melting pool decreases, the length remained unchanged, the cooling rate increase. After cooling, there is a large tensile stress on the surface of the model. As the depth increases, the tensile stress decreases rapidly and eventually becomes compressive stress.