Abstract: Broad band THz radiation has great protential application in wireless communications due to the following features: high data transfer rate, good directionality, high safety, low scattering,high transmittance, and so on. However, many technical problems, such as how to avoid absorption by water vapor and finding the most promising windows of transparency, need to be resolved. In this paper we review several key techniques and latest achievements in the research on long-path THz transmission through the atmosphere. Future trends and application prospects are also discussed.