Abstract: In order to use the low-frequency components of the pulsed eddy current signal to detect the crack defects in the steel plate effectively, a method of pulsed eddy current synchronous sampling was proposed. The working principle of pulsed eddy current synchronous sampling method was described. Different sizes of rectangular slot in the steel plate were processed to simulate the crack defects in steel plate. A transducer consisting of exciting coil and measurement coil was designed to pick up the pulsed eddy current signal. Signal acquisition was realized by the use of Data Acquisition Card. Based on LabVIEW, the synchronous sampling software was designed. Through the steel plate defect detection and the analysis of experimental data, it was indicated that the method of pulsed eddy current synchronous sampling had a high sensitivity in steel plate internal cracks defect detection and could effectively identify defects in steel plate.