The traditional laser line scanning method cannot acquire the color information of underwater targets. A red green blue (RGB) laser scanning method is proposed to design a 3D scanning system for underwater targets. RGB three primary colors laser combined into a beam of white light source, after calibrated by the calibration board, the underwater targets are scanned. The CCD camera is used to collect the color information of the targets, and the 3D reconstruction of the underwater targets is realized and the color information of the targets is obtained through computer algorithm. Reconstruction results show that the color reproduction of underwater targets is real and accurate. The method has the advantages of small computation, fast scanning speed and high efficiency. The 3D color information of underwater targets is acquired and reconstructed in real time.