The purpose of this study is to find out what leisure activities are effect the interpersonal relations of students with mental retardation. The subjects of this study employed 96 who attend at special school for the mentally retarded. 48(experimental group) of them who are in middle school(24 students) and high school(24 students) for the handicapped were trained LAP(Leisure Activity Program) as 49 lesson plans for fifty weeks. The other(control group, 48) employed 48 who are in middle school and high school for the handicapped and they are did not received LAP. The instrument used in this study were adapted Social Interpersonal Skills. The conclusion drawn from the results were as fellows. The findings of this study demonstrate that leisure activities on facilitating their interpersonal relations skills. Therefore, school should provide students with mental retardation with various leisure activities. and The researcher have a thought that when planning IEP(Individualized Education Program) fitting at the level of students, if manage the goal and object of leisure activities, effectiveness of the special education should be elevate.