In order to study the influence mechanism of surface roughness on cavitation corrosion,the cavitation corrosion experiments of 304 stainless steel samples with different surface roughness in 3.5%NaCl solution were conducted on ultrasonic vibration cavitation experiment device.By analyzing the mass loss,surface morphology,microhardness,and electrochemical performance changes of the samples,the influence of different surface roughness on the surface morphology and performance of cavitation corrosion was explored.The results show that cavitation pits occur on the sample surface after cavitation,and the pits mainly occur at the edge of the wear marks,exhibiting dual characteristics of corrosion and cavitation.With the increase of surface roughness,the density of cavitation pits increases and the mass loss of the samples becomes more serious.However,when the roughness reaches a certain value,cavitation erosion will reduce the surface roughness value and play a flat role.After cavitation corrosion,the sample surface shows a hardening phenomenon.But as the surface roughness increases,the surface hardening phenomenon of the sample weakens.After cavitation corrosion,the corrosion current of the sample increases,the corrosion potential shifts negatively.As the surface roughness increases,the change of corrosion potential and corrosion current of the samples increases,showing a continuous declining trend of corrosion resistance.