Abstract: Abstract：Objectives High stiffener web height I-girders on large cruise ships are made of welded thin plates, which produce noticeable weld distortion and stresses during manufacturing, and can affect the load-bearing characteristics of the structure. Methods Taking the 450mm I-girder as the investigation object, based on the actual welding parameters, the welding deformations and stresses were calculated by thermo-elastic-plastic finite element method, and as the initial state to carry out nonlinear finite element calculations to simulate the failure behavior of the structure under vertical Loads. Results The initial welding deformation would increase the instability of the structure when subjected to vertical compressive loads, which greatly weakened the ultimate load bearing capacity, and the reduction of the ultimate load reduced 35.74%. While the effect of the welding stress was less apparent compared to deformation. Conclusion The results of the investigation proved that the welding at the T-joint had an effect on the structural load-bearing characteristics, and the weakening effect of welding deformation should be considered in the calculation of the strength of the real ship structure and certain reinforcement or corrective measures should be adopted.