Abstract: Based on the CIVA simulation platform, the common metal sheet welds were taken as the research object, the EMAT parameters were optimized, modeling, simulation analysis and experimental research on the distribution of Lamb wave sound field in materials and the detection effect of artificial defects were carried out, and the effects of pulse-echo mode pitch-catch mode by using EMAT in detecting weld defects were compared. The results show that the EMAT optimized by simulation has high resolution ability to defects, and is very sensitive to the defects of butt welding of several common metal materials of 3-6mm ships. The EMAT detection method based on pitch-catch mode has stronger stability, higher detection efficiency and resolution, it is suitable for rapid detection of thin plate welds.