Abstract: The acoustic method can't realize high-accuracy seabed survey when the seabed environment noise and acoustic scattering influence are serious, so a scanning system based on line structured light is proposed. Generally, the laser center stripe extraction and the system parameter rapid calibration are the two key problems affecting the accuracy of line structured light sweeping system. In the laser center stripe processing, the multi-threshold algorithm can effectively filter out background noise by using different thresholds, and the Gauss fitting method based on the extreme value method is used to fit part of the laser stripe with Gauss function. A stripe centerline extraction algorithm is proposed by combining the multi-threshold algorithm with the Gauss fitting method based on the extreme value method. The algorithm has the accuracy of the Gauss fitting method while retaining the speed of the multi-threshold algorithm. For the parameter calibration of the system, a fast calibration method is proposed for collinear points. With the designed plane calibration target, the system parameters can be calibrated quickly and the seafloor can be scanned with high precision by determining only 3 collinear feature points. Finally, a model test is carried out in water tank to verify the feasibility and effectiveness of the proposed method.