本研究旨在探討一名18歲就讀高職，具生活適應困擾之輕度智能障礙個案，在個人中心遊戲治療中的改變歷程、遊戲治療的療效因子，以及研究對象生活適應困擾改善的情形。資料分析結果如下： 一、研究對象在個人中心遊戲治療中的改變歷程，呈現出四個階段的發展，依序為：關係建立階段、自我能力呈現階段、正負向情緒表達階段，以及正向問題處理階段；隨著各階段的發展，研究對象在遊戲室中更具自主性、更能開放表達個人內在的情感、呈現個人的能力，與發展正向的自我概念。 二、個人中心遊戲治療提供研究對象的療效因子包括有：安全的探索、感受到自我的能力、自主權的擁有、正向情感的經歷、負向情緒的發洩、內在世界的反應、洞識性的想法等八項。 三、個人中心遊戲治療的實施，並非在提升研究對象的智能表現，而是藉由遊戲作為諮商的媒介，提升研究對象自信心與自我正向的態度，表現在現實生活中，能擴展自己的活動範圍、主動性提高、較少依賴他人，與他人互動時，態度變得更為溫和、和諧，能與他人做良好的互動，並主動關懷、接納他人。

The purpose of the study was to investigate the impacts and therapeutic factors of the person-centered play therapy in improving the life inappropriate behaviors of an 18-year-old emotionally disturbed high school student with mental retardation. Eighteen sessions of play therapy were conducted, videotaped, and transcribed. Data were analyzed by using the approach of case study, qualitative research, and template analysis. Three main findings were: (1) the client changed gradually during the sessions, and the changes consisted of four stages, which were establishing rapport relationships, presenting self-capacity, expressing positive and negative emotions, and handling problems positively; the client became more and more confident, comfortably expressed personal emotions and capacities, and developed positive self-concept during the study; (2) the changes of the client may be partially caused by the experiences the client went through during the study, which were the feelings of security, the sensing of self-capacity, the achievement of autonomy, the perception of positive emotions, the release of negative emotions, the reaction to inner world, the establishment of rapport relationships, and the development of insight; (3) the person-centered play therapy may not try to elevate client's intelligence, but the approach can contribute in attaining self-confidence and positive attitude. As a result, the client expanded his own life experiences, depended less on others, and became more active, exhibited more tenderness and kindness while interacting with others.