In this paper，the vertical structure of the atmospheric boundary layer in Chongqing on summer after‐ noon is analyzed using the sounding data with intensive observation. The general features of the vertical structure of the atmospheric boundary layer under different weather conditions are also given. The results show that the atmospheric boundary layer depicts a typical convective boundary layer structure under clear and cloudy conditions. On clear days，the development of convective boundary layer is very vigorous，the surface transpiration/ evaporation is strong，and there is obvious upward water vapor transport. The near-surface superinsulation layer is thick，and the potential temperature lapse rate is large. The height of the boundary layer can reach 1. 5 km on average and up to 2. 1 km，while the height under cloudy conditions is relatively low，with an average height of 1. 0 km. Under sunny and cloudy conditions，the wind speed in the boundary layer is generally low with the values less than 5. 0 m·s-1. On cloudy days，the atmospheric boundary layer presents a classic morning boundary layer structure，which means that there is a stable boundary layer and a residual mixed layer between the convective boundary layer and the entrainment layer. Under this condition，the thickness of the convective boundary lay‐ er is relatively low，with a magnitude of less than 0. 8 km. The specific humidity profile presents a feature oppo‐ site to the potential temperature profile，and the boundary layer wind speed is relatively low. When it rains，the potential temperature depicts a neutral stratification feature and shows no obvious convective boundary layer structure. Due to the influence of different weather systems and processes，the characteristics of specific humidity and wind profiles are relatively complex and changeable.