A bridge is one kind of assembled steel truss concrete composite continuously ridged bridge , and the prefabricated bridge deck is connected with steel truss through the reliable welding between the steel truss and the shear connector, which has been pre buried in the bridge deck. For finding the bridge construction process to install the prefabricated bridge deck, which can make the steel truss and the deck in uniform and reasonable stress, initially putting forward three connection ways, one time connection, three batches connection, the whole batches connection. Using Midas Civil to create a whole bridge finite element model of space, and analyze these three kinds of coupling methods, obtaining that different connection ways have significant influence on mechanical property of the bridge. The results of the study show that, the bridge deck connected with the steel truss in whole batch connection way can make combination structure in most reasonable stress, more uniform deformation, and can effectively improve the bridge structure stiffness, besides, this connection way will be beneficial to later welding work. In this paper, the calculation results have been used in Guangdong Qing Qi Yong bridge design, at the same time, the calculation results can provide reference for similar bridge design and construction.