Abstract: Due to welded joint corrosion resistance and mechanical properties difference among various regions, the local corrosion is likely to appear in the welded joint. It seriously threatens the safety of pipeline operation, and it is need to predict the corrosion behaviour of welded joint. The finite element model of carbon steel welded joint is established based on the galvanic corrosion principle, combing the COMSOL software, the welded joint corrosion morphology under three kinds of temperature is predicted. Then the effect of weld reinforcement, the area ratio of weld metal and base metal, and weld metal defects on the weld metal corrosion rate were investigated with the model. The result showed that the finite element model not only can predict the corrosion behaviour of welded joint, and can provide the theory basis for the welded joint design of oil and gas pipeline.