Abstract: Objective This study aims to realize numerical simulation of welding temperature fields under arbitrary complex welding paths based on ANSYS. Methods A double-ellipsoidal heat source model was applied along a three-dimensional curved weld seam to impose welding thermal load, while element birth and death technique was employed to simulate filler metal deposition. The orientation of heat source was determined with both welding gun vector and tangent vector of heat source trajectory. The local coordinate system of heat source was converted into a quaternion representation to describe its spatial attitude, enabling 3D rotation operations and smooth interpolation between load steps. Furthermore, a weld segmentation-sorting algorithm was proposed to subdivide spatial curve weld seam and sequentially sort elements within each segment, thereby determining unit activation order during welding. Results The proposed method achieves automated heat source loading, element activation control, and automation of analysis process for complex path welding temperature field analysis. Conclusion This approach significantly reduces difficulty of implementing numerical simulations of welding temperature fields with complex paths, and the related algorithms provide valuable references for the development of automated welding simulation programs.