Abstract: With combination of electromagnetic acoustic technique and DSP application technology, a crack-inspection device based on electromagnetic acoustic technique was developed for effectively detecing the crack defects of thick-walled pipelines. Electromagnetic acoustic shear vertical wave could be excited under the control of DSP. The echo signal was extracted by DSP and detection result was finally displayed on a computer. Experiment showed that the device could realize a real time detection of crack defects that were deeper than 2 mm for a 35 mm thick pipeline.