A radiation fog which occurred for five successive days was observed with an Atmospheric Data Acquisition system, Vertical profiles of temperature, moisture and wind fields were obtained during formation and dissipation of the radiation fog. Based on these data, boundary layer features at different stages of the fog development are discussed in the article. Results suggest that temperature inversion plays an important role in the formation and growth of fog, while fog has also important effects on temperature, moisture and wind structures in the atmospheric boundary layer.