The wide difference in social security between North Korea and South Korea makes it hard to imagine an immediate systemic integration. Instead, this study explored how a “transitional dual system” may work for North Korea for a certain period of time after unification. This study is composed as follows. First, we examined the necessities, essential characteristics, and directions of the transitional dual system, and presented a plan for its implementation. Second, we looked into legal issues concerning the transitional dual system in terms of the violation of basic right, equal right, and social security eligibility right. Third, we examined the social security system and present conditions of North Korea concerning national rationing, wage and income security, social service, and healthcare security. Fourth, we studied the way to disassemble the social security system of North Korea and integrate it into South Korean system. Fifth, we examined the feasibility of introduction public assistance the vulnerable and low-income people in North Korea and discussed related issues. Sixth, we presented a plan for the application of the basic pension system of North Korea region. Seventh, we examined the basic principles and concrete policy measures to normalize healthcare system in North Korea.