Abstract: Two kinds of steady-state thermal loading of double ellipsoid heat source and entire weld seam were used to obtain the deformation and stress distribution of tubular structure, and verified by experiments. The results show that welding deformation and stress with the two kinds of loading mode have the same trend. The peak of welding deformation at entire seam loading is located in the middle of the seal plate. The peak value is 4.931 mm. Welding deformation at entire seam loading is close to experimental results. The peak of stress is similar, and the peak value is about 339 MPa, and close to experimental results. The simulation results meet the requirement of engineering application. It proved accuracy of the simulation results. The calculation time of double ellipsoid heat source loading is 27.2 times of entire seam loading. Considering engineering applications, entire seam loading has great use value in numerical simulation.