This study attempted to investigate the change of Cobb`s angle and postural stability of adolescents before-and-after a 12 weeks` 3 times per week exercise program. 37 adolescents with idiopathic scoliosis and over 10°of cobb`s angle, residing in Y Gun, Gyeonggi Province, were selected as the subjects for this study and divided into two different groups, such as the training group of 24 adolescents(m:3, f:21) and the control group of 13 adolescents(m:5, f:8). The study could come to the following conclusions. The training group showed the most significant reduction of Cobb`s angle against the thoracic spine angle(p < .01) and the lumbar spine angle(p < .01), and posture balance while there were significant improvements in the posture control function in all the training group(p < .01, p < .05), the control group didn`t show a large difference in the Improvement of posture control function. With the results above, it was found that Carrying out the twelve-week exercise program is effective in Improving the Cobb`s angle and postural stability of juveniles` with idiopathic scoliosis along.