Abstract: In order to study the construction technology of caisson in the actual projects in the Pearl River Delta region, this paper takes the sewage main pipe network project of Nanpu Island, Panyu District, Guangzhou as a case, and deeply discusses the construction technology of caisson, including measurement lofting, foundation pit excavation, cushion laying, formwork support, concrete mold removal and maintenance, caisson sinking and bottom sealing. The design calculation and key processes of the project are described in detail. The results show that it is feasible to use the caisson method in the soft soil layer. The undrained sinking method can significantly reduce the force of caisson structure in the sinking process, thus bringing a lot of convenience to construction. The results can provide reference for similar projects.