Abstract: Laser ultrasonic visualizing is a new type of inspection technology. Compared with traditional detection a method, this technology has the advantages of rapid detection, long-distance, and no detection blind areas. A detection technology based on three-dimensional maximum amplitude and three-dimensional wave field reconstruction detection algorithm for ultrasonic signal peak-to-peak values was studied. A laser ultrasonic visualization detection system with pulse laser excitation and piezoelectric probe receiving ultrasonic signals was established to detect surface crack defects in aluminum plates. The results showed that the laser ultrasonic visualization detection technology can quickly detect cracks defects on the surface of aluminum plates, and can display the position and size information of surface cracks in 3D, as well as real-time display of the propagation and reflection of 3D ultrasonic field.