The beam & girder and track installation works of Wuchuan slipway project is just on the main stream side of the Yangtze River where the water is deep and swift.According to the characteristics mentioned above,and due to the difficulties of high accuracy requirement of underwater track installation as well as the tight time limit,we combine the construction and measurement in the process of grillage beam prefabrication,assembly and installation,to provide reference for similar comb type slipway engineering.