Geographic information sharing emerged with the birth of human civilization, since ancient times people are sharing information to others. At present, geographic information sharing, which is supported by information technologies and network technologies, is a complex project that needs to solve the problems of technology, standard and policy. Geographic information sharing is related to many domains, such as national economic, political, military, and so on. The fundamental purpose of information sharing is to share the maximum use of resources. We have some approaches to do it: to increase the amount of information and to improve their quality, and to speed up the rate of information utilization. There are two ways to achieve the goal. Firstly, depending on science and technology, it reduces misunderstanding and uncertainties in information utilization, in other words, according to objective laws to understand and use information. Secondly, how to produce management rules which will be used as guideline for understanding information and using information from understanding which reflect objective laws accurately. All of these sharing behaviors for understanding and using information are done by people, and people's behavior also follows the economic rules and laws of social development. The core of today's theory of property rights is to encourage people to understand and apply objective things, in order to maximize their resources into social wealth. This paper discusses definition and purpose of geographic information sharing, and presents that geographic information sharing is a complicated system consisting of geographic information, information technologies, and information sharing rules. At the last, this paper analyzes the position of geographic information resources property in geographic information sharing.