Abstract: A three-group age structure can be designated as a point in the triangular diagram, while the routine of the points in time series traces the age structure evolution. The paper classifies the age structure evolution patterns of countries (areas) in the world and provinces in China, and discovers the general and ergodic age structure transition (AST) pattern which experiences three stages: the “bonus raising” stage (i.e., from the traditional fertile young population to fewer children-more labors population), the “debted ageing” stage (i.e., from fewer children-more labors population to fewer labors-more aged population), and the stage in between (i.e., turning stage). While developed countries are primarily in the middle of stage three, most developing countries are in the late phase of the first stage, and many least developed countries in Africa are still in the early stage one or even in the traditional position. Started in the 1950s and accelerated since the 1980s, the AST in China is now just passing the turning stage with diversifying decreasing bonuses at turning points from coast to inland provinces. According to a simulation scenario, China will approach the equilibrium position near 2100, with 15% children, 55% labor forces, and 30% older people, which is probably the common end of all countries in the future.

Keywords: Age Structure Transition, Triangular Diagram Routine, Bonus Turning Point, Age Structure Equilibrium

摘要： 将三段式年龄结构表示为三角图中的点，则其时序轨迹可以表达人口年龄结构演化过程。通过分类梳理世界各国（地区）及中国各省份人口年龄结构的演化模式，并预测中国人口年龄结构的长期均衡位置，发现人口年龄结构演化具有充分的“各态历经性”，可称为“年龄结构转变”，其基本路径是：从多子化的年轻型人口出发，经历少子红利化、转折和负债老龄化3个阶段到达少子-高龄型人口的长期均衡位置。发达国家（地区）已处于第三阶段中期，发展中国家（地区）多处于第一阶段中后期，最不发达的非洲国家（地区）还处于转变初期，甚至还在起点徘徊。中国人口年龄结构于2010年经过红利拐点进入第三阶段，加速赶上发达国家（地区）的转变进程。预测结果显示，2100年中国人口的均衡年龄结构为少儿占15%、劳动力占55%、老年人占30%，世界各国（地区）也会向这一方位聚拢。

关键词: 年龄结构转变, 三角图轨迹, 红利拐点, 年龄结构均衡