Abstract: Based on principle of ultrasonic focusing, the two-dimensional focusing of linear phased array probe is designed by means of acoustic lens. The simulation of sound field is compared with the common linear phased array and improved phased array acoustic field. Afterwards, C-scan images of the Cu-Fe joint are obtained experimentally. Theoretical analysis and experimental results show that the improved phased array system can effectively make the linear phased array probe to realize two dimensional focusing, and the C-scan results with conventional single crystal probe are in good agreement with the results. On the premise of ensuring the detection accuracy and reliability, the scanning efficiency has been significantly improved.