A technique of laser ultrasonic imaging is proposed to detect austenitic stainless steel weld with artificical defects. Austenitic stainless steel weld is scanned using the pulse of NdYAG laser, and the received ultrasonic wave is transformed by discrete sine/cosine transform (DST/DCT) and Hilbert transform (HT). The conventional ultrasound imaging method can not effectively detect the weld edge and the artificical defect, however, laser ultrasound imaging technology, which combines DST/DCT and HT, can not only directly and efficiently detect the weld edge, but can also detect the location, the shape and the size of damage in the weld. Therefore, the laser ultrasound imaging technology based on the discrete sine/cosine transform and Hilbert transform provides the basis for quantiative detection.