Quality control of gravel leveling is an important prerequisite for successful installation of the immersed tube tunnel during construction.Taking the immersed tube tunnel foundation gravel leveling project of the Shenzhen-Zhongshan Link as an example，aiming at the high-precision construction requirement of ±4 cm proposed for this project，we put forward a series of optimization adjustments to the multibeam measurement method based on the construction site，propose a direct depth calibration method to improve precision，and compare and verify the multibeam data by multiple methods，such as point method and line method etc.The results show that this multibeam sounding technology can meet the engineering requirements.The application of the multibeam sounding technology can meet the result detection of multiple stages of construction，such as gravel leveling and backfilling of tube.