Abstract: This article analyzes the phenomenon of “separated but keep together” in four rural families in Micun，Yunnan Province，in response to the question of “what makes a family”. It reflects on and expands the fixed division of family structure and boundaries at the experiential level. The study has found that the ever-changing family forms are just ways to adapt to social changes，which means the current family form is a “temporary solution”. Once a farmer's family encounters a major disruption，the sudden changes in the family's internal situation or external conditions force responsible family members to make compromises and breakthroughs in personal life and economic functions. The process of resolving conflicts manifests as the process of readjusting the relationship between individuals and families to achieve a new balance. Therefore，the survival and prosperity of the vertical axis structure of the family has always been the goal，constituting the most fundamental action logic of each family member. This is the force that unites peasant families. In the current urban-rural relationship，the scattered family structure is a result of farmers'necessity for livelihood. The dispersion of rural family forms does not necessarily mean the occurrence of individualized trends among rural residents. The core purpose of the family drives the dispersion of family forms，and the ethical responsibility transcends space and exerts a binding force on family members scattered in various places. Finally，this article links the actions of family members with the family structure，emphasizing the purpose and principles of action from the perspective of individual family members，while not denying the role of external factors such as economic status. The family structure does not constitute a constraint on the actions of family members，rather，it is the result of the decisions made by family members in accordance with behaviour ethics during the transition period. Economic factors are only a means of contributing to or making it more tortuous to this process.

Key words: urban-rural relationship, family structure, ethics of responsibility, family form, longitudinal spindle structure