Secure Boot is to ensure the security during the system booting procedure. Through the protection of the booting process, the Chain of Trust for the whole system is set up to maintain the security of the post operation environments. This paper presents a brief introduction of the Secure Boot technique. In addition, three actual applications of the Secure Boot are introduced in this paper. Through introducing the principle and application cases, we do wish the readers of this paper would be able to have more understanding of Secure Boot.