Osteoarthritis is considered as the most common joint disease of humans and one of the most common causes of chronic disability among elderly people in the developed countries. The main objective of the present research was to determine the impact of 8 weeks of the combined exercises on the balance and the amount of pain of patients with knee osteoarthritis. 15 patients with knee arthritis were selected purposefully and in form of convenience and they participated in this research. The patients implemented the Training Protocol of walking in water and land and the knee locking and the front thigh exercises for 8 weeks. Dynamic balance (Y test) and pain (McGill questionnaire) of patients with knee arthritis were measured and evaluated before and after eight weeks of combined exercises. The data were analyzed by use of the t-dependent (P˂0.05). In the dynamic balance of patients with knee arthritis, there was significant difference regarding the anterior side between before-exercises (39.9 7.2) and after-exercises (50.7 6.8), regarding the internal posterior side between before-exercises (28.8 9.2) and after-exercises (38.0 8.7), regarding the external posterior direction between before-exercises (37.5 7.2) and after-exercises (44.4 7.4). (P˂0.05). Regarding sense perception of pain by patients, there was significant difference between before-exercises (2.2 0.6) and after-exercises (1.8 0.5), regarding the emotional perception of pain by patients between beforeexercises (1.5 0.3) and after-exercises (1.2 0.3) and on perceiving variety of pain by patients between before- (2.1 0.8) and after-practices (1.8 0.7) (P˂0.05). From the findings of the present research we can conclude that the hydrotherapy exercises combined with exercises on land can cause to improve the dynamic balance and the pain of patients with knee arthritis; therefore we can recommend it as a modality for these patients.