所谓人口老龄化是指老年人口在总人口中的比例日益增长并呈上升趋势的现象。通常是以一国或地区的老年人口比重（老年人口60岁或60岁以上人口同全部人口比）、少年儿童比重（0-14岁少年儿童人口同全部人口比）、老少比（60岁或65岁以上人口同0-14岁少年儿童人口比）、年龄中位数（把人口分为两半的年龄，一半人口高于这个年龄，一半人口低于这个年龄）等指标综合使用来衡量该国或地区是否进入老龄化以及老龄化的程度。国际上公认，一个国家或地区的人口中65岁以上的老年人口比重超过7%（或60岁以上老年人口的比重超过10%），0-14岁少年儿童比重低于30%，老少比在30%以上，年龄中位数大于30岁，这些指标多数达到以上标准就视为该国或地区人口状态呈现为老年型，人口已经进入老龄化。

The so-called aging of populations is refers to the old population to grow and to assume the trend of escalation day by day in the total population proportion the phenomenon. Usually is by a country either the local old population proportion (old population 60 years old or above 60 years old population with the entire population compared to), the youth proportion (0-14 year-old youth population with the entire population ratio), the whole families compares (60 years old of either above 65 years old population with 0-14 year-old youth population ratio), the age median (divides into population two halves age, half population is higher than this age, half population is lower than this age) and so on target synthesis uses to weigh this country or the area whether to enter the aging as well as the aging degree. Internationally the recognition, a national either in the local population 65 year-old above old population proportion surpasses 7% (or above 60 years old population proportion surpasses 10%), 0-14 year-old youth proportion is lower than 30%, the whole families compared to above 30%, the age median is bigger than 30 years old, these targets achieve the above standard regard as most this country or the local population condition present for the old age, the population already entered the aging.