Abstract: Aiming at the difficulty of nondestructive testing of pressure vessels head part, a piezoelectric ultrasonic guided wave array is proposed for pressure vessel damage localization. Firstly, a finite element model of the head part of pressure vessel is established, and the narrow-band of Lamb wave is excited to simulate the echo of the damage. Secondly, discrete the monitored area into sparse points, the time of flight (TOF) of array signal at each sparse points is obtained as the sparse feature of the guided wave array, and calculates the root mean square (RMS) value of them to form the damage sparse feature sample library. Finally, the RMS of the measured array signal when a damage happen is calculated to match the damage sparse feature sample library for damage imaging, and the highest position of the pixel is the position of damage occurred. The test results show that the simulated damage distance positioning error is 20 mm and the angle positioning error is 1°, which is more consistent with the actual damage position and can accurately reflect the position of the defect.