Abstract: Information security classified protection is a basic system of China’s information security protection. Conducting information security classified protection in colleges and universities is not only a key content in strengthening national information security work, but also an effective measure to improve the information security level of university networks. The paper first summarizes common information subsystems in China’s universities and colleges, describes the functions of these subsystems and offers the recommended classified protection levels for these subsystems. Then, this paper divides an university information system into various modules based on security domain according to the security strategy of “all Grade II systems forming one security domain and each Grade III forming one security domain” and gives the access control methods for security domain boundaries. Finally, according to the requirements on Grade II systems by China’s national standards concerning classified protection, this paper analyzes the contents and objectives of security construction for Grade II security domains from five aspects, thus offering a reference for universities to conduct classified protection based information security construction.