Abstract: Objective Effect of stress relief treatments on corrosion resistance of 316L welded joints was examined in this paper. It aimed to understand how welding residual stress affected corrosion resistance of austenitic stainless steel welded joints and enhance their corrosion resistance, thereby providing a scientific foundation for the improved performance. Methods High-frequency impact technology was employed for stress relief treatment on 316L welded joints, and changes of residual stress in welding heat affected zone near fusion line before and after stress relief were tested. Corrosion resistance of weld zone was evaluated by electrochemical methods and slow strain rate tensile tests. Results The results indicated that high-frequency impact stress relief treatment transformed residual stress in welded joints from tensile to compressive stress. This transformation significantly increased pitting potential of weld and heat affected zone, widened and stabilized passivation range, and improved intergranular corrosion resistance. Stress corrosion resistance of welded joints was greatly improved, and stress corrosion cracking time increased by 4 times. Conclusion There was a significant difference in intergranular corrosion and stress corrosion resistance before and after stress relief. Unlike solely considering influence of chromium-depleted zones on corrosion resistance, effect of residual stress on corrosion resistance of austenitic stainless steel must not be overlooked. On one hand, residual stress impaired pitting corrosion resistance by increasing defects in passivation film. On the other hand, residual tensile stress could promote anodic dissolution at crack tips, thereby reducing intergranular corrosion and stress corrosion resistance. The compressive stress induced by high-frequency impact stress relief treatment reduced crack propagation tendency at the crack tip, significantly improving corrosion resistance of austenitic stainless steel.