Abstract: The paper introduce a series of key designing technology for forest resources geographic information system based on Xihu county.These designing technology include:the functions of system,management of spatial database,management of forest resources database,link of forest resources database and spatial database,charting of forest resources map.Many functions can be performed by the system,such as:input and output of data,editing operation,update and safeguard of database,information retrieval,statistic analysis etc.Some special information and map can be produced in accordance with regionalization and planning of the forestry production and operating activities.There are many layers in the spatial database,such as administrative boundary layer of each class,highway layer of each class,river system layer of each class,railway layer,contour layer,forest resources layer,and forestry programming layer etc.The organization of the database were divided into two types.One is subcompartment investigation data,including 62 fields of ground factor,tree measure factor,and scattered trees factor.Another is code data,including 13 fields of factors code,country name code,town name code,village name code.