Recently as psychiatric mental health nursing focuses on the psychiatric patients` social rehabilitation after discharging, we can see the trend of more practical and substential rehabilitation of more practical and substential rehabilitation therapies being developed and improved. Psychiatric client experience deterioration of social functioning, deficits in social skills and dysfunctional inter-relationships. Those who has mental disability spend the rest of their life suffering from their handicap. Even after the discharge, lack of social skills and difficulties in adjusting to reality, draw them act to relapse or rehospitalization. Thus appropriate rehabilitation program will improve social adjustment increase self-esteem develop positive interpersonal relationship and further more it will prevent them from regression. The purpose of this study is to verify the effectiveness of social skills training program in improving the psychiatric client` social functioning. To serve the purpose of the study outpatient with OPD treatment and community psychiatric patient were selected to test effect of social sill training. The effect of social skill traing will be evaluated by comparity the consequences of relationship change, social behavior, positive and negative syndrome before and after the experiment. Also cases will be based on the result the case will be analyzed individually to prove the case changing scores. The following are these results of the analysis of the 2 cases. 1. Interpersonal relationship score of case 1 was biggest increased from 56 score to 88 score by 32 score. Case 2 showed the increase from 55 score to 73 score. Both of these result was possible due to effective role play and feedback. 2. Social behavior score improved from 67 score to 89 score by social skills training for case 1. For case 3, Social behavior score improved from 61 score to 80 score social sill training was merely focused on correcting non-verbal communication skill(ex : eye contact) and the results showed great deal of improvement. 3. The positive and negative syndrome score of case 1 decreased from 50 score to 36 score by 14 score. Case 2 also decreased from 78 to 60 score by 18 score. Case showed difficulties in expressed negative feeling(ex anger) but improved after the training. Therefore, regardless of individual differences, there were improvements in relationship change, social behavior, and positive & negative syndrome. In other words, limitations of this program were first, the short program practice period, secondly, lack of case. Based on the results of this study, it is concluded that the social skills training program is a very valuable intervention method for psychiatric mental health nursing. Therefore if the studies, applied in actual situation, which based on the study were continuously conducted, it will contribute to psychiaric patient` interpersonal relationship and social rehabilitaion.