To counter the problems in the Yangtze River 12.5 m deepwater channel phase II project Hechangzhou section soft mattress detection and cross-section control of deepwater submerged dike under conditions of deep water and large flow velocity,we compare multiple underwater detection methods,and apply the Sonic 2024 multi-beam detection technique for the first time to the control of soft mattress,deepwater bagged sand and underwater riprapping in the construction of underwater regulating works,by which,accurate data concerning the image,location and elevation of underwater structures are obtained and visualized and quantitative analysis of underwater concealed works are realized to guide the construction.