The objectives of this research were to know the use of mass media in Ban Doi Chair, Lumphon Province, and to understand the village's communication structures which affected the progress of development activities. The emphasis was place on the discovery of three structures : communication structure, friendship structure, and knowledge authority structure. The data collection was done by the local village teachers in a month. All 177 heads of households were interviews. The findings were that the people of Ban Doi Chair most frequently used radio. However, television has increased its popularity recently. The research indentified three structures which were very complex. The three structures were different. The indexes of the structures were provided in order to make more clear understanding of structures. The researcher concluded that to understand these three structures would make the information diffusion about the development activities smoothly flown in Ban Doi Chair.