The purpose of this study is to verify whether the nature-centered art therapy program is effective in improving the psychological well-being of mothers of the underprivileged. To achieve this research purpose, a preliminary program was designed based on previous research analysis and needs survey, and through implementation and evaluation, the main program was finalized for a total of 10 sessions, once a week, 70 minutes per session. To verify the effectiveness, 32 mothers of children attending three local children's centers located in city A were selected as research subjects. After assigning research subjects to experimental and control groups, a nature-centered art therapy program was conducted to derive quantitative and qualitative evaluations. Psychological well-being measures were performed before and after the experimental group and the control group, and the SPSS WIN 22.0 program was used for statistical analysis. For qualitative analysis, after filming the video, three observers recorded the subject's behavioral observations and memoranda to analyze the core language corresponding to the sub-area of psychological well-being. This program had statistically significant effects in the areas of self-acceptance, positive interpersonal relationships, environmental control, life purpose, and personal growth among the overall psychological well-being and sub-areas of mothers of the underprivileged. Therefore, this study is significant in that it demonstrates the effectiveness of group programs, especially the usefulness of natural media, and provides clinical basic data and practical programs that can be applied in the clinical field by developing programs that are more comfortable and safe for underprivileged mothers.