Abstract: With the development of hypersonic vehicles, the large-scale conventional hypersonic wind tunnel with nozzle exit diameter of 2m order of magnitude is required. However, the energy consumption of the exhausting working air also increases dramatically in the large-scale tunnel. How to save energy while the simulation conditions for the development of hypersonic vehicles are satisfied has become an important problem to be considered in the design of the conventional hypersonic wind tunnel. To solve this problem, the layout of the conventional hypersonic wind tunnel is optimized as follows:first, the aerodynamic layouts of the existing conventional hypersonic wind tunnels are summarized; second, the energy transformation in the conventional hypersonic wind tunnel during its operation is theoretically analyzed, and from the point of view of saving energy also analyzed are the methods used to deal with the exhausting working air in different layouts; third, the possible methods for utilizing the remainder energy of the exhausting working air are discussed; finally, an optimized layout for the large-scale conventional hypersonic wind tunnel is put forward, and the critical technologies to be used in the realization of the layout are discussed. The result of a simple calculation of saved energy in the optimized layout under a typical run condition shows its advantages in saving energy.