This study was designed to determine the effects of community based mental health rehabilitation program on perceived family support of mentally ill patients. Quasi experimental design, single group repeated measure, was used to carry out the research The subjects were consisted of 6 chronic mentally ill patients who lived with their family members in the community and participated in community based mental health rehabilitation program of Seungbuk Pubic Health Center. The instruments used for this study was 20 items of family support scale, which was developed by Ji Won Park(1985) and revised by the researchers to 5 likert type scale. The data were gathered from August 1. 1996 to August 31. 1997, and analyzed using paired t-test and one way ANOVA with SPSS PC. The results of this study were as follow : The main hypothesis `There will be differences in the score of perceived family support measured by (six month intervals) of mentally ill patients participated in the community based mental health rehabilitation program` was rejected(F=3.356, p=.557) The subhypothesis 1 `There will be a differences in the score of perceived family support between the first months` : the subhypothesis 2 `There will be difference in the score of same scale between the second six months` : and the subhypotheis 3 `There will b a difference in the score of same scale and after 12 months of the participation in community based mental health rehabilitation program were all rejected(t=1.26 p=.220, t=-.49 p=.627, t=-1.49 p=.149)`.