Abstract: Objective To explore the basis to discriminate diminished criminal responsibility.Methods Chi-square test,one-way ANOVA test,factor analysis and stepwise discriminant analyses were conducted for92cases which were divided into three groups according to the degree of diminished criminal respon-sibility.Results There were significant differences in the type of crime and rating score among three groups.The factor1reflecting the premeditation and preparation before crime was the most important of all factors.Realistic motivation,time selectivity of offending,emotion during the crime,understanding the nature of the behavioral,impairment of life ability and impairment of reality testing were the discriminat-ing factors of grades division in diminished criminal responsibility.Conclusion The diminished criminal responsibility in mental disorder offender could be divided into three grades.

Key words: mental disorder, diminished criminal responsibility, three grades division1