Abstract: A high-power ultrasonic cavitation facility was used to investigate the cavitation erosion behavior of 316 L welded joints before and after PWHT in liquid LBE at 550 ℃. After different time of cavitation erosion test, SEM and AFM were used to analyze the surface topography, roughness and hardness. It is found that the roughness and the maximum erosion depth increase with the increase of erosion time, and work hardening is found on all the surface of welded joints with and without solution treatment. Plastic deformation appears on the surface of welded joint without solution treatment, and after solution treatment, the hardness of welded joint increases greatly but the plasticity is decreased. The results and analyses showed that the welded joint with solution treatment exhibits better cavitation erosion resistance.