This study is a case study that examined changes in resilience and self-harm behavior by performing client-centered collage art therapy for early adult women. The subject of the study was a 25-year-old woman, and the treatment period was conducted once a week for a total of 18 sessions, 60 minutes. In order to evaluate the psychological level of the research subject, a resilience test, a Baum Test, and a Landscape Montage Technique were performed. In order to examine the changes in the research subjects, self-expression and behavioral changes were analyzed for each session, and the pre- and post-mortem changes in the objectivity scale and projective picture test were analyzed. The results of this study are as follows. First, collage art therapy was effective in stopping self-expression and non-suicide self-harm behavior of research subjects. Second, self-regulation ability, interpersonal relationship ability, and positivity, which are sub-areas of the resilience scale, all improved, and communication ability improved the most among the nine sub-factors. Third, it was consistent with the psychological and behavioral changes in the research subject, resilience, Baum Test, and Landscape Montage Techniques, and the frustrated desire and negative emotions of the research subject remained stable and changed to hope and expectation for oneself.