Abstract: In the paper, ultrasonic linear array, cross array and clock-type array are used to image for defects of a thin plate with elliptical location method. According to Lamb wave propagation in the plate, the excitation signal and its parameters are selected and a model of ultrasonic signal detection is built up. Imaging is made based on the principle of elliptical trajectory and whether defects exist in the plate was determined. Excitation signal is generated by the piezoelectric ceramic wafer. Above-mentioned three kinds of arrays are used to acquire signals, which are then processed and imaged. The results show that it is effective to use cross array and clock-type array to do defect imaging and remove the effect of ghost generated in the process of imaging.