The gymnasium and natatorium of Hangzhou Olympic Sports Center are the main stadiums of Hangzhou Asian Games in 2022. The roofs of gymnasium and natatorium are connected as a whole through the central hall. The steel roofs of the gymnasium and natatorium adopt the structure of double-layer latticed shell and the roof of the central hall is a single-layer latticed shell with heteromorphic surface.There is a single-layer cantilever lattice shell structure on the east and west sides of the gymnasium and natatorium. The natatorium and gymnasium roof can be divided into double-layer reticulated shell, single-layer reticulated shell, boundary truss, gate arch truss, etc.Steel roof members have various forms and complex joints, which are composed of bending-torsion L-shaped beam, bending-torsion box members of variable section and "drum" joints. The steel roof has the characteristics of complex shape and large span. Also the construction period of the project is tight, there are many specialties and high quality requirements The key and difficult points of steel roof construction in various stages, such as deepening design, manufacturing, field installation and digital information management, were introduced.During the construction process, the construction environment of the whole structure was complex, the deepening processing of components and joints was difficult, and the installation configuration was difficult to control, there were many aerial operations and high welding quality requirements. The key construction techniques and methods in the construction stage of hyperbolic reticulated shell roof were emphatically expounded. The construction organization of "information organization and management, process interpenetration, time limit and land limitation" was adopted to solve the construction difficulties of various disciplines in large stadiums and gymnasiums. The double construction scheme of "large traveling tower crane block hoisting combined with local hydraulic integral lifting" solved the difficulties of tight construction period and high quality requirements of the project, and realized the key technology of large tonnage tower crane working on the floor and floor arc walking; the working method of "floor multi-point assembly and high-altitude local butt joint" solved the stress concentration of all welded structure and ensures the high quality and safety of the structure with low risk. The measurement, positioning and installation technology of special-shaped curved surface structure realized the installation accuracy of single-layer special-shaped curved surface roof composed of bending and torsion members. The data obtained from the simulation analysis of the whole process of structural installation, closure and unloading by the finite element analysis software provided sufficient scientific basis for the construction process control. Through the comparative analysis of the simulation theoretical data and the measured data, the feasibility of the construction technology was verified, which provided important reference value for the follow-up similar projects. Through the combination of theory and practice, the key construction technology described in this paper solved the technical problems of steel roof construction of gymnasium and natatorium of Hangzhou Olympic Sports Center. The results showed that the construction was safe and reliable; the quality could meet the requirements of specifications and design, and realized the idea of "green, intelligent, thrifty and civilized".