Abstract: After summarizing design of the forest resources geographic information system and researching the plugin technology, this paper put forward an integration solution which constructs forest resources GIS based on plugin technology .The new idea about forest resources GIS integration was analyzed, which not only provided a nice reusable and flexible develop environment, but also supported special fields faced developers when they put in practice some application project. The advantages of forest resources GIS integration were also introduced. The article describes the development process of this system which divided into three parts: plugin engine, host program and plugin instances, explains these three parts’ effects in plugin system. According to the key technologies such as generic and interface, the author elucidated how to realize the plugin system using Microsoft .Net technology. In the end, a case was demonstrated to explain the whole development process and the main functions.