目的　探讨精神发育迟滞者发生危害行为的相关因素。　方法　对 1992至 2 0 0 1年司法精神病鉴定为精神发育迟滞的危害行为人 41例进行分析。　结果　精神发育迟滞者发生危害行为的以盗窃占首位 ,凶杀、纵火次之 ,多见于家庭监护能力差、明显受社会歧视的 30岁以下的未婚青年男性。　结论　精神发育迟滞者引起违法行为是社会不安定的因素之一 ,应尽快建立健全相关的法律法规 ,确实加强监护、管理。 Objective To explore the related factors of harmful behavior in mental retardation. Methods A total of 41 cases of psychiatric patients with mental retardation from 1992 to 2001 were analyzed. Results In the case of mental retardation, those who committed harassment took the lead in theft, followed by homicide and arson. They were more common in unmarried young men under the age of 30, who were poorly guardian of the family and were obviously discriminated against by society. Conclusion Mental retardation caused illegal behavior is one of the factors of social instability, as soon as possible to establish and improve relevant laws and regulations, strengthen supervision and management.