China experienced an early arrival of aged society around the turn of the century due to its rapid demographic transition．In order to keep the equilibrium development of population，it is essential to address the dilemma of the large population size and the unbalanced population structure under cer- tain resource，technology and institution conditions．If the government implements the universal two- child policy in time，and further adjusts the population and related socio-economic policies to increase TFＲto about 1. 8 and then gradually make it return to the replacement level，a stable population will be approximately achieved in the next 30 or 40 years．The age structure，together with the urban and rural composition will both reach a stable level．The proportion of population aged 60 or over will reach one- third，which is almost the average level of developed countries as a whole but still lower than that of Germany and Japan，and the urbanization rate will reach 75 percent．At that time，the human capital accumulation will rank forefront among the world，the modernization will be realized，and the balance among the factors of population itself and the development of economy，society，resources and envi- ronment is expected to be maintained．

China experienced an early arrival of aged society around the turn of the century due to its rapid demographic transition．In order to keep the equilibrium development of population，it is essential to address the dilemma of the large population size and the unbalanced population structure under certain resource，technology and institution conditions．If the government implements the universal two- child policy in time，and further adjusts the population and related socio-economic policies to increase TFR to about 1. 8 and then gradually make it return to the replacement level，a stable population will be approximately achieved in the next 30 or 40 years．The age structure，together with the urban and rural composition will both reach a stable level．The proportion of population aged 60 or over will reach one- third，which is almost the average level of developed countries as a whole but still lower than that of Germany and Japan，and the urbanization rate will reach 75 percent．At that time，the human capital accumulation will rank forefront among the world，the modernization will be realized，and the balance among the factors of population itself and the development of economy，society，resources and envi- ronment is expected to be maintained．

Abstract: Since the year 2012 saw a turning point of China s working age population，the issue of population ageing has increasingly been attached wide － spread significance to China s economic growth and national development In measuring population ageing，the traditional indicator of percentage aged 65 ( or 60) or over fails to capture the influence on ageing of the increased life expectancy Therefore，new measurement of ageing needs to be considered from the perspective of prospective age by which expected remaining years of life can be taken into account Two indicators，i e ，per-
centage of the elderly with prospective age of 65 or over ( with the year 2000 as reference) and proportion of the elderly with remaining life expectancy below 15 ( inclusive) ，are computed for China over the period from 2000 to 2050 using China s census and survey data and population projections In terms of the new measurement，levels of ageing and dependency ratio in China would be much lower，and the pace of ageing much slower，with the proportion of the elderly in the mid－century being 4－5 percent-
age points less than that from the traditional measurement A comprehensive understanding and thus holistic strategies are necessary to better achieve healthy ageing.