In the ten-odd years of running of the basic old-age insurance system，the substitution rate of pension in respect of the social average wage has been in continuous decrease，and now is lower than the target level（60%）. This is attributed to shrinkage of payment base，lower minimum payment years，earlier retirement age（especially female）and lower yield of personal account. This has caused insufficient security of personal pension，and is unfavorable to break even and sustainable development of the system. As a result，it is necessary to separate personal accounts for market-oriented investment and operation from the perspectives of systemic framework and parameter setting，and reform systemic parameters，especially payment base，payment years，retirement age（especially female）and yield of personal account. In particular，the objective of wide coverage shall not be achieved by over-lowering the threshold.