Abstract: Underground diaphragm wall has been widely used in foundation pit engineering，but the construction quality of the joint of the diaphragm wall has not been effectively solved. In order to investigate the engineering problem of how to detect the concrete compactness at the H-section steel joints of underground diaphragm wall，this paper takes the ultra-deep and large foundation pit diaphragm wall of Zhongyi Road Metro Station of Wuhan Urban Rail Transit Line 12 as the research background，introduces the detection principle of the acoustic transmission method，and studies the concrete compactness scheme at the H-section steel joints of the ground diaphragm wall by the acoustic transmission method. The results show that the sound wave transmission method has good engineering value in detecting the compactness of H-section steel of ground joint wall. The field test results are more consistent with the trial design. Through analysis and summary，the acoustic parameter database with different density can be obtained in order to provide scientific guidance and decision for its practical application.