Abstract: China’s social old-age insurance system is a typical unbalance structure separating of urban and rural regions. Rural residents do not have equal rights of social insurance comparing with the urban residents, which result from the institutional fragmentation and restrict the establishment of a unified and equal labor market. The urban and rural social old-age insurance system is a necessary path and demand for eliminating the system difference and realizing the coordination of economic and social development in urban and rural areas. Based on the background and the challenge of Inner Mongolia’s social old-age insurance system, the coordination of urban and rural social old-age insurance system is proposed to achieve and balance an effective link between the two types of urban and rural systems under the leadership of government by three steps.