In the 21st century, it is highly required to develop a better security management system to prevent many severe accidents occurred in the sea because it has been growing both size and importance for industries and global business which are heavily related to the sea. In this paper, we proposed a new theoretical criteria for three core decisions to make for SAR(search and rescue). These are three decisions for search scope, search assets, and search duration. We first brought up several issues and problems of current SAR system, and then studies all related factors of these three decisions for SAR operations. This paper provides a theoretical foundation of SAR operations by applying a theoretical approach and reasonable standards.