The research was to investigate the effect of sexual acknowledge and attitude of elderly on life satisfaction. It conducted an investigation about 222 elderly who facilitate C elderly center, B district and G city. Data analysis was conducted by ANOVA, frequency and multiple regression with SPSS/PC. As a result of analysis on sexual knowledge level based on general characteristics, a group of subjects who had spouse, family member with him or her, higher education level than elementary school, and hoppy was appeared to be higher. And based on sexual attitude, a group of subject who had age over 80, other family type, elementary school graduates and other religion was appeared to be lower. As a result of analysis on life satisfaction based on general characteristics, a group of subjects who had age over 80, other family type, elementary school graduates, other religion and hoppy was higher. It was found that a level of sexual knowledge and attitude of elderly affects the life satisfaction about 33.1%. Sexual knowledge based on general characteristics has different effect on sexual attitude and life satisfaction. As sexual knowledge affects the sexual attitude and life satisfaction, it is needed to intervene sexual knowledge of elderly by education and management, and to help the attitude and life satisfaction to be positive for them.