Modeling is a common method of scientific knowledge, especially in the domains where conducting real experiments involves high financial costs or is physically impossible. This method enables researchers to create simplified models of complex systems, which makes it possible to analyze and study their behavior in various conditions. In a general sense, modeling can be described as an experimental approach to examining real-world systems based on their models. The diagram illustrates the modeling of the library user service process in a general way. The scheme includes the flows (incoming, outgoing, managing, and resource) to detail into the library operation. In addition, the author provides the generalized schemes of two models of higher education institution’s library, namely reactive and proactive ones. The service schemes are complemented with generalized schemes of modeling algorithm of the library user service process.