To explore the mechanism of the effect of neuroticism on the abnormal psychology of drug-related offenders, Eysenck Personality Questionnaire-Revised Short Scale for Chinese(EPQ-RSC), Chinese Offenders Psychological Assessment-Personality Inventory(COPA-PI), Dispositional Moral Sensitivity Questionnaires(DMSQ), and a Self-compiled Questionnaire on the Reform Situation of Offenders were utilized to survey 1,961 drug-related offenders in two prisons in Yunnan Province. The results demonstrated that neuroticism was significantly positively correlated with their abnormal psychology and regulating moral sensitivity, and significantly negatively correlated with the their reform situation. Moreover, dispositional moral sensitivity played a partial mediating role between neuroticism and abnormal psychology. Moreover, their reform situation modulated the effect of dispositional moral sensitivity on abnormal psychology. Based on the dual-process model of moral sensitivity, the study revealed the internal mechanism of the formation of abnormal psychology and provided a reference basis for interventions targeting abnormal psychology among drug-related offenders.