Objective : This study is designed to find out the effects of Rainbow Power therapy on knee joint with osteoarthritis. Methods : Patient with the osteoarthritis of knee joints are divided into Rainbow Power therapy group(20 people) and none-Rainbow Power therapy group(20 people). After treatment, we evaluated the effect per each group. Results : 1. Fifty and Sixty aged patients were the most in the Rainbow Power group(30% each) and sixty aged patients were the most in the None-Rainbow Power group(45%). 2. In the both groups, 1-3 years duration of disease was the most(40%, 45% each). 3. In the none-Rainbow Power group, patients improved (Lysholm score : $49.20{pm}11.54{ ightarrow}63.90{pm}9.54$, p<0.05), but, did not improved in the part of squatting and dystrophy. In the Rainbow Power group, patients improved(Lysholm score : $46.55{pm}9.89{ ightarrow}80.90{pm}13.78$, p<0.05), but, did not improved only in the part of dystrophy. 4. The effects of treatment by VNRS were follow : After treatment, $4.10{pm}1.22$ in Rainbow Power Group and $4.55{pm}1.15$ in none-Rainbow Power group. 5. The effects of treatment by nine points scale were follow : In the Rainbow Power group, the Excellent was 7 cases(35%), the Good was 9 cases(45%), the Fair was 4 cases(20%) and there was no Poor. The Excellent was 6 cases(30%), the Good was 8 cases(40%), the Fair was 6 cases(30%) and there was no Poor.