With the extensive development of urban underground space, the depth of diaphragm wall has been increasing, and some ultra-deep diaphragm wall has exceeded 50m, which brings challenges to site construction. Taking Wujiayao Station subway foundation pit of Tianjin Metro Line 11 as the engineering background, this paper summarizes the construction quality control measures of 91 57m deep underground diaphragm walls, innovatively adopts hydraulic lifting platform to assist reinforcement cage docking, and analyzes the effect after completion of the construction of the diaphragm wall through engineering monitoring data. This paper summarizes the construction techniques and quality control measures in the troughs and cage construction of diaphragm wall and concrete pouring under the condition of soft soil with rich water, and provides reference for the design and construction of ultra-deep diaphragm wall in similar soft soil areas.