Numerical simulation concerning the forming and welding process of spiral welded pipe was conducted, which included three steps: the first step was the stress analysis when the spiral was formed, and then the stress was regarded as initial condition of melding during the temperature field analysis in the process of welding, the last step was the thermal stress analysis of the weld seam after the welding was over. Moreover, when the steel strip was pushed, the stress was also calculated by non-linearity contact technology using Abaqus Software. By finite element modeling and calculating of the forming and welding process of the spiral welded pipe, the key points of the multi-fields synthetic simulating were studied and discussed.