Since 1970s，Southeast Asian countries have realized the transformation of the population reproductionpattern，and entered the period of demographic dividend successively. In the next few decades，Southeast Asian countries are still in the period ofdemographic dividend. Whether those countries can make full use of their abundant labor force resource and then turn it into demographic dividend determines whether their economy can achieve the leaping development. Based on the research method of demographic dividend，this paper expounds the formation and development process of demographic dividend in Southeast Asian countries，analyzes the relationship between demographic dividend and economic growth，labor market，consumption and savings，and discusses the basic characteristics and laws of demographic dividend in Southeast Asia.