This study is about improving the methodologies for social security financial projection. By reviewing domestic and foreign financial projection situations, it suggests that in order to set the correct direction for social security systems in the face of rapidly changing populations and economic conditions, financial projection methodologies need to be advanced. The study classifies and reviews three types of financial projection models that can be used for this purpose and presents a plan to improve the way financial projection has been combined without consistent standards. Furthermore, it argues that this plan is significant because it meets the leading practice of the OECD and allows for both macro and micro policy analysis.