To investigate the differences of psychological characters among the mentally retarded, the normal, and the gifted students, 240 subjects, composed of three intelligence groups with equal sex, were drawn from the EMR classes (MR group), the normal classes (N group), and the gifted classes (G group) in Taipei area. The subjects were measured by the following tests: Self Concept Inventory, Achievement Motivation Questionnaire, General Anxiety Scale for Children, Test Anxiety Scale for Children, and Intellectual Academic Responsibility Questionnaire. By means of Correlation analysis and 3 (groups)×2(sex) ANOVA, it was found that: (1) The MR group was significant inferior to the other groups in self-concept, achievement motivation, and internal responsibility, while there was no significant differences between the N group and the G group; (2) Male students gained significant higher scores in self identification and lower scores in both general and test anxiety than female students; (3) Male students manifested higher self acceptance and achievement motivation in both N and G groups, while the opposite was true for the MR group. It seems that mental retardation is not only a deficit in intellgence, but might also lead to a disadvantage in psychological adjustment