In ancient China, the feudal lords believed that the grand-generation symbolized success and wealth; in contrast, the women who could not give birth to enough children would be desolated by the family and were forced to share husbands with other women. Under such a cultural background, the population in China grew rapidly without any restrictions. But now, considering the disastrous outcomes brought by rapid population growth, leaders begin to figure out some efficient methods to control such a situation. In fact, the problem of overpopulation not only exists in China, but also appears around the world, especially in most developing countries. Thus, Coming up with policies that apply to different national condition to alleviate overpopulation pressure has become a crucial task for worldwide leaders. Population control is necessary in most countries because overpopulation leads to irreversible problems: the destruction of environment, the decrease of people's living standard and the higher frequency of social instability. It is possible that low birth rate will lead to economic degeneration to some extent. For example, because of the low birthrate in Japan, the percentage of retirees in all citizens grew from 5 percent to 22 percent during the past fifty years so that Japan's upside-down age pyramid comes into being, which means that the aging population has exceed the young people to a large extent (Glazer, 2008). As the example states, the reduction of labor force due to the decrease of birthrate will undermine total output, leading to the economic degradation. However, maybe the drop of young workface caused by low birth rates can decrease the production in a country, but the labor productivity will increase from another perspective so that each employee can reflect their greatest value. In addition, in most developing countries with population explosion, the degradation of economy caused by limited physical capital but overmuch labor is more serious than created by the shortage of staff. Thus, it is still necessary to control population for a better future. The first reason to control population is that the overpopulation condition has put threat to the environment that people live in. T