Abstract: Metal 3D printing is rapidly advancing and widely used in aerospace, medical, automotive, and construction. However, its complex process challenges traditional quality control methods. Laser ultrasonic testing (LUT), offering non-contact operation, real-time capability, and high sensitivity, has become vital for quality inspection in metal additive manufacturing.This review covers LUT application progress in metal 3D printing. It first outlines metal 3D printing fundamentals, processes, and applications. Next, it explains LUT principles and system setup, including wave propagation and equipment, highlighting its advantages for inspecting complex surfaces and internal defects.The paper details LUT's specific uses in metal 3D printing, especially defect detection, reviewing advances in LUT for both conventional and 3D-printed metals. It also discusses future applications within the AM process.Finally, considering current trends, the paper suggests combining LUT with other methods to improve metal 3D-printed part quality, proposing novel approaches.