This study aimed to investigate how the attachment-separation relationship changes between parents and children. To attain data, this study adopted qualitative methodology, mainly suing qualitatively deep interviews to collect data. Seven adolescents, who had run away from home for more than one year, were interviewed. Analyzed with grounded theory and assisted by MAXQDA software, the research presents the following findings: The attachment-separation relationship between parents and children variesd in accordance with the runaway-from-home processes. Each stages correspond with different states of attachment-separation, which include “attachment-separation discrepancy” “going toward separation” “the state of separation” “going toward attachment” “adjustment of attachment-separation” “balance of attachment-separation”. “adjustment of attachment-separation” “balance of attachment-separation”. The first five states were experienced by all the interviewees, while the other one was experience only some of the interviewees. Among those adolescents whose family structures had been damaged, their parent-child attachment showed identification transference. Congenial parent-child link contributes to adolescents’ devlepoment in autonomic behavior. Though runaway teenagers temporarily disconnect the family link and can enjoy much more space for autonomic behavior, the need for family link and the family damage remain negatively affecting teenagers’ development aboard. Premature independence can put adolescents in more crises. Based on the research findings above, the study also offered some suggestions on related practices and future research as reference for personnel in education, counseling, guidance, and social work.