First from the public library and government information disclosure of the relevant theory, to extend the service and the government information open system concepts are analyzed, and then find the service to carry out theoretical support, such as asymmetric information theory. 首先从公共图书馆和政府信息公开的相关理论出发,对延伸服务和政府信息公开制度的概念进行了剖析,然后找到这一服务开展的理论支撑,如信息不对称理论等。