中文摘要：

流浪儿童流浪的原因与动力机制是流浪儿童群体研究的一个主要领域。流浪儿童外出流浪的原因错综复杂，关系个人、家庭、学校、社会乃至政府的政策制度等各个层面。以制度变迁的视角切入，从社会保障制度、婚姻制度、城乡隔离制度、宗族制度等几个方面，对与流浪儿童流浪相关联的制度与制度变迁因素展开分析，提出制度变迁因素是儿童流浪的主要因素。

英文摘要：

The study of the causes of the vagrancy of the wandering children and their motive mechanism is a popular focus in the study of the vagrant children as a group. The causes are complicated and related to the personal, family, school, society, government and policy. In the perspective of institutional changes, the paper discusses the social security system, the marriage system, the urban - rural separation system and the clan system and concludes that the institutional changes are the key cause for their vagrancy.