Abstract: Large boundary-layer wind tunnel is necessary equipment for wind engineering re-search.In the background of the development of Zhejiang University ZD-1 boundary layer wind tunnel,the key technical problems in the design of the aerodynamic and vertical structure of the large recirculating boundary layer wind tunnel are introduced in detail.Test section of ZD-1 wind tunnel is designed as 4m width and 3m height,the maximum wind speed is designed as 55m/s, and the turbulence intensity is designed as not higher than 0 .5%.With the contraction ratio of 4∶1 ,single test section and single loop aerodynamic profile are used in aerodynamic design,e-quivalent diffusion angle of 0.22°is arranged in the test section,and the shape of corner vane is treated specially.The combination of steel structure and concrete structure is used in the vertical wind tunnel structure design.The results of flow field calibration show that the maximum wind speed of wind tunnel reaches 55m/s,the maximum energy ratio reaches 2.0,the hydrodynamic stability coefficient in master test area for wind speed of 40m/s is less than 0.5%,the maximum axial static pressure gradient is 0.0044,and the maximum turbulence intensity is 0.47%.It is showed that all the indexes meet the design requirements,and some indicators reach the standard of aviation wind tunnel.It is worth stressing that setting axial diffusion angle in the test section can reduce axial static pressure gradient,and the dynamic pressure nonuniformity coefficient con-tour shows the characteristics of horizontal distribution in the test section,which confirms that the uniformity of dynamic pressure for horizontal direction is better than vertical direction.Verti-cal structure design plays a certain role for improving the level of horizontal uniformity of the test section,which provides a reference for the design and construction of similar wind tunnels.