Abstract: When leaky circular waveguide is used in the urban mass transportation, its radiation characteristic might be influenced by the complicate environment, which further affects the quality of the wireless communication. In this paper, using snow coverage as examples, the influences of snow coverage thickness and volumetric wetness on the radiation characteristics of leaky circular waveguide are discussed, the way of reducing the influence of snow coverage is proposed. It is shown by the results that the accumulated snow has significant influence on the near field distributions of the leaky waveguide, and the far field of the leaky circular waveguide is decreased with snow thickness and volumetric wetness. By covering a foam layer on the leaky waveguide, the influence of snow coverage on the radiation characteristics of leaky waveguide can be decreased effectively, therefore, the reliability of the wireless communication systems can be improved.