The purpose of this study is to analyze in depth how to reset the role of the existing social insurance system according to the basic income introduction discussion and operation method. To this end, we examined basic income and social insurance the philosophical background, social conditions, operational principles, effectiveness. When discussing the introduction of basic income and resetting the role of social insurance through the comparison of characteristics of social insurance and basic income, the income preservation function of social insurance and basic income are coexisted. In this case, the basic income is provided at the intermediate level, but if social insurance benefits are caused by social risks, the basic level of income is reduced. The alternative to social insurance is to maintain the basic income level at the highest level and to absorb the income preservation benefits of existing social insurance. However, it is assumed that in-kind benefits held by social insurance other than income preservation benefits are maintained. Based on the analysis of the National Pension Insurance Panel Survey data and the statistical annual report, the appropriate salary level for basic income in consideration of the income level for old age is estimated to be between 500,000 and 1 million won. But above all, social consensus on the introduction of basic income should be reached.