Abstract: In this paper, the finite element analysis module for simulating the welding process is developed based on the open finite element analysis software SiPESC.FEMS, which is part of the integrated computational simulation platform SiPESC. This module can map the node temperature field obtained from the thermal transient analysis of the welding process to the mechanical analysis in the form of thermal load. It can fully consider the influence of temperature change on the structural performance during the welding process, and realise the numerical simulation of thermo-mechanical coupling in the whole process of the structure. It also supports multi-step analysis, which can simulate multiple welding stages and complex welding processes. Thermal transient analysis can be used to simulate non-linear transient heat transfer processes in welding. It can support multiple types of welding moving heat sources, commonly used thermal element types, as well as complex boundary conditions such as thermal convection and thermal radiation. Mechanical analyses of welded structures, can support customisation of temperature-dependent mechanical material parameters, and support constitutive models such as thermo-elasticity and thermo-elastoplasticity. There is a numerical analysis and comparison using an example of welding along the outer side of a hollow cylinder and a perforated square plate. The example uses a sequential thermomechanical coupling analysis method. The welding thermal analysis process is transient heat conduction calculation, and the structural static analysis process is a thermo-elastoplastic calculation. The calculation results are compared with those from ABAQUS, a widely used commercial computer aided engineering(CAE) software, the maximum temperature deviation is 0.000482%, the maximum displacement deviation is 0.0231%, and the maximum equivalent plastic strain is identical. The calculation accuracy of this analysis module is essentially consistent with that of ABAQUS, which validates the effectiveness of this welding module and its capability to solve practical engineering problems.