Abstract: By integrating operating experience, accident analysis, risk assessment and defense-in-depth philosophy into decision-making consideration, risk-informed regulation better focuses regulatory attention to an issue consistent with its risk significance, which facilitates the establishment of appropriate regulation without damaging nuclear safety at the same time. By referring to the inspection findings from nuclear safety regulatory organizations of China, this paper utilizes the mitigating system performance indicator（MSPI） and significance determination process（SDP） in the study. From perspectives of basic theory,instance analysis and regulatory application consideration, this paper analyzes the correlation and difference between MSPI and SDP. The work could provide reference for the application and promotion of risk-informed regulation approaches.