Abstract:[Objective] To evaluate the effects of physical exercise on quality of life and clinical manifestations of mild to moderate knee osteoarthritis (KOA). [Methods] A total of 76 patients who visited Outpatients Department of Joint Surgery of our hospital for Kell- gren-Lawrence grade I to II KOA from September 2022 to December 2022 were included in this study. The general data of patients were collected, and the World Health Organization Quality-of-Life Scale (WHOQOL-Brief), as well as HSS, KOOS, WOMAC scores and knee flexion-extension range of motion (ROM) were measured for evaluating the quality of life and clinical manifestations. Univariate compari- son, Pearson correlation analysis and logistic regression analysis were conducted on the data. [Results] Of the 76 patients included into this study, 29 patients fall into the exercise group, accounting for 38.2%, while the remaining 47 patients were classified as the non-exercise group, accounting for 61.8%. The exercise group proved significantly lower than the non-exercise group in terms of BMI [(23.8±1.3) vs (25.0±1.7), P=0.002], as well as incidence of diabetes (62.0% vs 91.8%, P<0.001), hypertension (75.9% vs 91.8%, P=0.010) and coronary heart disease (65.5% vs 87.2%, P<0.001), while the former had significantly higher levels of education and personal income than the latter (P<0.05). However, there were no significant differences between the two groups in age, sex, course of disease, number of knee side in- volved, and imaging K-L grade (P>0.05). The exercise groups was significantly greater than the non-exercise group in terms of WHOQOLBrief scores, including physical health [(63.8±4.8) vs (54.6±3.4), P<0.001], mental health [(62.6±5.3) vs (53.7±3.4), P<0.001], social rela-tions (60.9±5.0) vs (53.6± 3.1), P<0.001] and the surrounding environment [(61.6±4.5) vs (54.0±4.8), P<0.001], as well as the HSS score [(74.1±4.2) vs (68.3 ±2.5), P<0.001], KOOS score [(73.7±4.1) vs (68.4±3.3), P<0.001] and knee ROM [(139.3±9.2)° vs (129.4±13.3)°, P= 0.001], while the former got significantly lower WOMAC score than the latter [(31.2±5.8) vs (43.3±3.0), P<0.001]. The WHOQOL-Brief scores were significantly positively correlated with HSS, KOOS and knee ROM (P<0.05), whereas significantly negatively correlated with WOMAC score (P<0.05). As results of logistic regression the high social relationship score was a positive factor for exercise participation (OR=0.664, P=0.026), while high WOMAC was a risk factor for non-exercise participation (OR=1.681, P=0.001). [Conclusion] Physical exercise does control BMI, reduce the incidences of chronic diseases, and improve quality of life and clinical manifestations in patients with mild to moderate KOA. There is a correlation between WHOQOL-Brief score and clinical score, and WOMAC score could better reflect the situation of the patients.