Abstract: For the laser sealing process of the silicon-aluminum housing of the star-borne components, the transient stress and thermal effects degree are different depending on the different starting point of the welding. Therefore, a method based on temperature and stress simulation is proposed to determine the starting point of laser welding during sealing. The complex welding path with a circular arc angle is equivalently processed using the ANSYS platform to calculate the transient temperature field, the transient welding stress for long paths is calculated using a segmented parallel method. The results obtained the transient forces, heat, and weak links of laser welding under different starting points, and the safest starting point was predicted. This technology can be applied to different shell structures, avoiding design defects, improving the sealing qualification rate of products.