The installation and demolition of Bailey truss support system of Three Gorges Project ship lift belongs to be grade separation operation. Because of the narrow construction site, high construction strength, and big construction disturbance, the installation and demolition of Bailey truss has been one of the construction problems of Three Gorges Project. The installation and demolition technology system of bailey truss support system has been established based on the analysis of construction environment and the characteristics and requirements of different parts. The technology system contains the layout of construction equipment, the division of lifting units, the set of lifting point, and demolition plans of different parts and so on. This technology system ensures the smooth implementation of the installation and demolition of bailey truss. Construction schedule, cost, and safety of this project have achieved good results, and this technology system can provide a reference for similar project.