SCC sensitive areas of welded specimens in the marine environment was investigated by means of magnetic field distribution detection, residual stress measurement and corrosion morphology observation. The study found that both HAZ and parent material surfaces of welded specimens could generate high-level stress concentration areas under the action of marine environment, thereby becoming sensitive areas of SCC. The combined effect of residual stress and corrosion damage results in the formation of SCC sensitive areas. Meanwhile, SCC sensibility on HAZ and parent material surfaces are determined by residual stress level and corrosion damage degree on the structure surface, respectively. Appropriate preventive measures should be taken according to the determinant of HAZ and parent material surfaces’ SCC sensibility when SCC preventive measures of X65 pipeline structure servicing in the marine environment are designed.