Abstract: The theory research on “the lost only child family” focused on the perspective of problems at first and it could really help us to have a better understanding of this issue. But the research on the perspective of problems ignored the abilities and resources owned by the family members of “the lost only child family”, the perspective of strengths was a supplement. The practical intervention research explored the conditions of the family members of “the lost only child family” and the practical intervention methods by the relevant professional practices. This type of research shifted the research paradigm on “the lost only child family” from “perspective of theory” to “perspective of practical intervention”, while it was still at primary stage as a whole. The social policy research discussed the deficiencies of the existing policies and offered some relevant suggestions from two categories of social security and social assistance. While the orientation of “the lost only child family” social policy is not clear and the research on specific policies is not sufficient. As a summary, we can promote the development of the research on “the lost only child family” by increasing the number of practical intervention research and research classification as well as making an intensive study of the micro psychological problems of the family members, clearing the orientation of “the lost only child family” social policy and increasing the number of research on specific policies.