Combining with the characteristics of the underwater installation of trapezoidal hollow members in deep water with high flow velocity in Yizheng waterway regulation project of phase II project of 12.5 m deep water channel below Nanjing in the Yangtze River，we develop the installation special spreader，supporting measuring rack and measuring positioning system，and improve the composite dike component installation technology in the traditional waterway improvement. The installation equipment can improve the installation accuracy and construction efficiency，effectively solve the problem of axis deviation，misalignment，and difficulty in seam width control in the underwater installation environment，and achieve the expected goals of installing large components in deep water with safety，efficiency and high precision.