Based on the data of AQI and wind profiler for the whole year of 2015, the daily variation characteristics of boundary layer under severe polluted weather conditions in Beijing were analyzed. The results show that: (1) Wind speed is very small at severe pollution weather, especially near-surface wind speed is nearly 0 m/s. Vertical wind velocity is evenly distributed. Layer is gentle and boundary layer is stable and almost undulating. (2) The existence of high concentrations of pollutants blocked the transmission of solar radiation on the ground, while the surface of the long-wave radiation is difficult to spread, it will be accumulated to the development when upward to a certain extent. The lack of thermal power makes the boundary layer more stable. The stable boundary layer is not conducive to the spread of pollutants, and the formation of a stable boundary layer is conducive to pollution weather maintenance. This process forms a vicious circle of mutual promotion between pollutants and stable boundary layers. (3) The dynamical effect of the wind field is insufficient, the thermal turbulence plays the leading role, and the turbulence intensity is much smaller than that of the clear sky.