This paper aims to analyze the unity of freedom and equality in library rights system, and puts forward a view for the research of the justice nature of library rights. It points out that freedom and equality are not a pair of totally harmonious concepts, and the tense between freedom and equality goes along with the development of human rights. As the core content of system justice, freedom and equality provide value reference for the development of library rights. By analyzing the relationship between freedom and equality, we can master the original intention in the development of library rights more accurately as well as ensure the freedom and equality at the same time when users use the library resources. Freedom is the precondition and principle of the system so that users can have access to information without any constraint. The library has to propose the claim for freedom and equality in the development of library rights system, and the system justice is the unification foundation of library freedom and equality. Through system construction, the library needs to confirm the role and responsibility of the government in the realization of library freedom and equality.