Abstract: In this paper，we argue that the current standard age partition of populations into three broad age groups is difficult to capture the social-economic meaning of contemporary populations in the context of the extension of life expectancy，the enhancement of education of children and teenagers，the crude definition of adult age，and the changing social roles for older population. In this work，we try to divide population age into five groups according to a hundred-year life expectancy，and name each group correspondingly. The new partition which divides age groups equally not only makes statistical analysis and internal comparison easier，but also exactly conveys the life characteristics and social roles for each course of life，and thus can contribute to public policy adjustment. The demographic conditions are well under way for this age partition adjustment in both more developed countries and current China.

Keywords: Population Age Group , The Age Group of 60-79 , Younger Elderly , The Oldest-old

摘要： 文章基于当代人口平均预期寿命明显延长，青少年人口受教育年限不断提高，成年人口界定过于宽泛，老年人口群体社会角色明显分化的变化态势，指出传统的三大人口组年龄划分标准已难以真实体现当代人口年龄所内含的社会经济蕴意。鉴此，文章将人生百岁预设为正常的人口生命时限，按每20 岁为一个人口年龄段划分为5 个年龄组，并赋予各年龄组相应名称，据以建构契合当代人口生命历程与社会角色的人口年龄组别。新的年龄分组不仅使人口生命时段在岁月流变中形成均分格局，便于统计和比较; 而且使各年龄段的生命内涵与社会角色表达更加贴切，为适时调整社会公共政策提供依据。研究认为，无论放眼世界，还是聚焦中国，年龄结构调整的人口条件都已经或正在呈现。

关键词: 人口年龄组, 实年组, 年轻老人, 高龄老人