Abstract: The corrosion behavior of weld joint various regions with two kinds of heat input welding joint was studied by observing the welding joint microstructure and measuring the open circuit potential, polarization curves and galvanic corrosion current. Results show that the corrosion resistance in each region of weld joint with a small heat input as follows: the parent metal < weld metal< heat affected zone; the corrosion resistance in each region of weld joint with a large heat input as follows: the parent metal < heat affected zone < weld metal. The results are related with the different zones microstructure of weld joint. Compared two kinds of weld joint total corrosion rate, the large heat input joint has better corrosion resistance.