This utility model discloses a construction platform for installing air-ductless steel longitudinal beams in cable-stayed bridges, relating to the field of cable-stayed bridge steel beam installation technology. It includes a construction platform with a side support fixedly connected to one side of its top. Telescopic horizontal bars are installed at the four corners of the top of the platform, with pulleys installed at the ends of the horizontal bars. Steel longitudinal beams are installed on the side supports, and side protective components are installed around the perimeter of the platform. This utility model solves the problems of complex construction and difficult movement of traditional platforms by integrating the construction platform and telescopic horizontal bars. It is convenient to install and allows for flexible position adjustment, significantly accelerating the installation progress of the steel longitudinal beams. Furthermore, the side protective components reduce the risk of worker falls. The fixed connection between the side supports and the steel longitudinal beams ensures precise alignment between the platform and the main beam of the cable-stayed bridge. It adapts to the special structure of air-ductless steel longitudinal beams, and the telescopic horizontal bars can smoothly pass through the transverse diaphragms of the steel longitudinal beams.