Upon years of development，especially the accelerated construction as of the 1990s，China has preliminarily formed a social security system that covers social welfare，social insurance and social assistance and plays an important role in alleviating poverty，assuring living and pushing employment. Upon superimposed effects of accelerated urbanization，increased stress from economic downturn and problems left over by history，new problems and conflicts in security level，management efficiency and sustainability are continuously exposed from some systems. Given this，we have to carefully study and assess the present situation，summarize experience and lessons，and seize the time for systemic building based on objective and fair evaluation on effects of systems.