Abstract: The structure of the Xiongan Supercomputer cloud project is novel in shape, and the spatial relationship is complex. The floor under the roof is split-level, so it is difficult to choose the installation plan and support layout. Therefore, it is necessary to choose a reasonable support unloading sequence to ensure the safety of the structure unloading. The roof steel structure adopted the diagonal cross grid truss structure system, and the truss strings were inclined to each other. The west side of the grid truss extended down in an arc to the sealing beam, and then the roof load was transferred to the lower frame through the curved curved torsion V-shaped support of the variable section. The east side of the grid truss connected with the three-dimensional arch truss, and a small number of round steel pipe strings were arranged in the span to form the long-span spatial structure. The deep design technology was used to optimize the joint design of the long-span structure, so that the bending and twisting V-shaped support processing could meet the demands of the structural force transmission and architectural modeling. According to the structural system and layout characteristics of the project, through the horizontal comparative analysis of the support system, construction difficulty, safety management difficulty, schedule and construction cost of the three schemes, such as lifting scheme, sliding scheme and hoisting scheme, the optimal segmented in-situ hoisting scheme was selected. The east stereoscopic arch truss divided the arch truss into the upper and lower trusses reasonably according to the structure. The next trusses set the support for sectional installation and positioning. At the same time, the next trusses provided the fulcrum to support the previous trusses, which solved the construction problem that the arch trusses are high in height and heavy in weight and difficult to install. The long-span oblique grid truss was divided into reasonable segments, and the multi-span portal support system adopts tower crane to install the roof cross grid truss in segments, and adopted cross stabilizer rod to temporarily fix the structure during the installation process, which solved the construction problem of stability outside the plane during the single piece installation of grid truss and ensures the installation accuracy of the truss structure. The installation sequence of multiple tower cranes advancing from the corner of the roof structure to the core area not only solved the problem that each step of installation can form a temporary stable system to ensure construction safety, but also improved the construction progress through simultaneous installation of multiple cranes, providing a reference for the installation of other long-span truss structures. MIDAS/Gen, a finite element analysis software, was used to calculate the influence of temperature stress on the unloading of long-span cross grid structure. The unloading simulation analysis and comparison of long-span cross truss with different combinations of temperature stress and unloading direction were carried out under multiple working conditions, and the stress-strain nephogram of the maximum stress and maximum deformation of the structure were analyzed. The simulation calculation showed that, the role of temperature stress should be considered in the unloading of multi-fulminated long-span cross truss, and the unloading sequence should be taken from the mid-span support with large deformation. The structural temperature during unloading should be close to that during the installation, so as to reduce the stress caused by the change of structural construction temperature and ensure the safety of structure construction.