The application of long-span continuous steel truss-concrete composite girder bridge is very rare in the highway bridge, and the study on the construction, monitoring and related problems of long-span composite structure bridge is still in the exploratory stage. Based on a continuous truss composite girder bridge project, a new pullout-not-shear-resistant key is adopted, and the traditional pouring sequence of concrete bridge deck is adjusted, which greatly improves the anti-cracking performance of negative moment concrete. In the construction stage of the bridge, the displacements in the disassembly mid-span, the precompression stress of the mid-span concrete, the slip of the bridge deck and the steel beam are the key contents of the bridge monitoring. In order to achieve the design goal of the state of bridge, it is very important to accurately and effectively monitor the construction. The monitoring results are compared with the theoretical data of the finite element analysis software to analyze and judge the safety of construction process, and ensure the smooth construction of the whole bridge.