This thesis analyzes SELinux-based policies to implement Mandatory Access Control and improve the security and reliability of the system by verifying data integrity and trusted paths. In terms of attack detection and defense, this paper also proposes corresponding malicious behavior detection and defense techniques for side-channel attacks. By collating and analyzing domestic and international research on SELinux technology, we summarize the research progress of SELinux in virtualization, cloud computing, containers and Android security, which can provide some reference and support for the security of Kunpeng-based domestic server and desktop operating systems.