Abstract: Propagation characteristics of ultrasonic surface wave on the surface of 430 stainless steel were studied experimentally under the conditoin of electrolytic hydrogen charging.Surface wave transducer ABWML-4ST-90°and PCI ultrasonic card were used to collect ultrasonic data.Ultrasonic attenuation coefficient was calculated,and the microhardness was tested before and after hydrogen charging.The results showed that the ultrasonic attenuation coefficient increased clearly with the electrolytic hydrogen charging,while the ultrasonic velocity decreased markedly and there was a almost linear relationship between the velocity and hydrogen concentration.The attenuation coefficient and the velocity became almost constant after the material surface was in the stage of hydrogen saturation.The microhardness of the hydrogen attacked material decreased obviously.