Abstract: The fundamental meaning, function, formation background and developing process of Geographic Information System(GIS) are introduced in the paper. The authors review and analyze the current development and application of geographic information system in forestry systematically, such as the research on forest resources information management, the study in forest management optimization and subsidiary decision-making system, the analysis of forest classification management compartmentalizing, the research on the function of distributing sample point, the application of forest thematic maps, the study on the design of afforestation project,the analysis of forest fire prevention, the study on the management of forest plant disease and pest control, the research on WebGIS of forest resources, the fundamental meaning of precision forestry.