Cast-in-place concrete is partly below the surface of the water in the Dai estuary fishing port west bank line repair and reconstruction project,the installation of underwater formwork and pouring concrete underwater are used in construction.We propose a cantilever rigid underwater template,and introduce the characteristics of this underwater template from several aspects such as the design idea,the construction technology and method of the field installation.The results show that the cantilever rigid underwater template can transform underwater problems into land solutions,meet the overall stability of underwater template under the action of concrete side pressure,and ensure the installation accuracy requirement of underwater template at a low cost.This technology has good application effect,which can provide references for the similar projects.