GIS-based mapping and decision support system has been efficiently and widely used in many different fields and domains. In practice, however, the application in forestry is still relatively limited, especially the large-scale mapping and specialized software development, which has witnessed a growing market from various customers. Supported by National High Technology Research and Development Program of China, this research designs and implements a new Forest Form Mapping System for China's Forest Resource, as well as a platform for research, education and decision support towards sustainable environmental management. It demonstrated how GPS data and the second national survey data can be integrated, visualized, and reported in a.NET and ArcEngine based system. In recognizing its flexibility in architecture and friendly user interface, it is suitable for a variety of applications in forest resource management.