Objective: This study measure the knee kinematics during gait analysis to confirm the effects of oral collagen on rehabilitation of knee osteoarthritis. Methods: Sixteen patients with level I and II knee osteoarthritis were recruited in this study. The WOMAC questionnaire was used to measure the symptoms of knee joint in patients. The KneeKG 3D evaluation system was used to measure the knee kinematics. The Pair t-test was applied to assess the significance in knee kinematics after three months oral Undenatured Collagen Type II (UC II), and the statistical significance was set at α = 0.05. Results: After oral UC II, the feeling of knee joint pain, stiffness, and the difficulty of daily life were reduced. In addition, knee flexion angle was increased from 51.8±15.2°to 58.4±10.7° (P<0.05), and knee varus angle was decreased to 2.1±4.8°. Conclusion: Taking UC II for three months can play a role in rehabilitation for patients with early knee osteoarthritis. The knee range of motion is close to the level of healthy elderly, and this also improving the symptoms of knee varus.