本論文檢視接受安置機構少年自殘的頻率、方式與理由，以及影響他們進入安置機構後自殘行爲的相關因素。在具完整資料者的545位安置少年中，進入安置機構後還曾經自殘時人占50.0%，頻率則以「偶爾」者最多(33.9%)，其次依序為「只有一次」(29.8%)、「有時」(25.2%)、「常常」(11.2%)。在自殘方式方面，最多人使用過的方式爲「割傷或劃傷」、其次爲「撞牆或其他異物」；多數少年將自殘作爲抒解內心負向情緒的主要策略。多元順序邏輯迴歸分析結果顯示女性、安置前自殘頻率越高、憂鬱情緒越嚴重、對機構紀範的感受越負面、身邊越多同儕曾經自殘者，其安置後自殘頻率越高，對自殘之認同程度對同儕自殘經驗所產生的中介效果不強，同儕自殘經驗和少年安置後自殘頻率間在有直接關係。本研究建議機構主動評估少年的自殘經驗與情緒狀況，協助他們學習處理負面情緒的方法，積極處理個案以避免同儕仿效，以及建構合理的機構規範，以期有效降低安置少年自殘行爲發生的可能性。

The objectives of this study were to explore the patterns of self-mutilation, including prevalence, reasons, and methods used among youth in residential group care, and to examine factors associated with their self-mutilating behavior after living in the institution. Among 545 respondents with completed data, 50.0% participants had engaged in self-mutilation after placement. Among them, 33.9% said they ”seldom” did it, 29.8% said they ”sometimes” did it, and 11.2% said they ”often” did it. In terms of reasons, most reported they did so to reduce aversive emotions or thoughts, such as anger, stress, pain, loneliness, and unpleasant memories. Multivariate ordinal logistic regression analyses revealed that frequency of self mutilation after placement could be predicted by gender, depressive symptoms, attitudes toward institutional regulations, and association with self-mutilating peers. Acceptance of self-mutilation played a weak mediating effect between association with self-mutilation peers and the frequency of self-mutilation. The study suggests that all residents should be screened for their emotional State and risk of self-mutilation. Related professionals need to teach high risk youth strategies of handling negative emotions, to prevent contagious among peers, and to set up reasonable regulations in the institutions.