Abstract: In this paper the design and implementation of knowledge based geographic information system are discussed. An object oriented relation frame semantic data model and new physical data structure are proposed. In the system advanced distributed tactics is used to implement data distributed query and update between different nodes. Also the system possesses the functions of the computer aided decision based on knowledge and models and the friendly adaptive human computer interface. The test shows that the system has the advantages, such as high intelligence, good distributed functions and convenient for use.