Taking the main line bridge and ramp JSW steel beam erection project of Wanjiali Elevated Bridge -- a core node of the Changsha Xiangfu Road Rapid Reconstruction Project as an example, the rapid installation technology of overline urban interchanges under limited working space is discussed. The Wanjiali Interchange has a total of five layers with the complex structure, difficult construction and high safety risks. After comprehensive comparison and selection of multiple schemes, the scheme of using QUY260 crawler crane in conjunction with super-large tower crane D5200 and STT3330 for steel beam hoisting is ultimately selected. The practice has proved that this scheme effectively solves the problems of small urban land space and difficult traffic dispersion, reduces the cost investment, and minimizes the impact on urban traffic efficiency.