Objective To investigate the prevalence of knee osteoarthritis in the elderly in Pudong New District in Shanghai, and explore the related risk factors. Methods With cluster stratified multistage random sampling method, 1 499 registered residents aged no less than 40 years in Shanggang Community in Pudong New District in Shanghai were selected for questionnaire survey. The contents of survey included name, sex, educational level, vocation, height, body weight, waist circumference, joint symptoms, past disease history, environment, recipes and living habit, and the risk factors for knee osteoarthritis were investigated with univariate and multivariate analysis. Results The prevalence of knee osteoarthritis was 33.3% (41.6% for females, 24.0% for males), which was increased with age. Stepwise Logistic regression analysis of factors possibly related to knee osteoarthritis revealed that old age, female, overweight/obesity, a lot of housework, family history of osteoarthritis, knee trauma, cold environment, prolonged standing and walking were the risk factors for knee osteoarthritis, while education, physical exercise, labor intensity, recipes, moist environment, drinking, smoking, wearing high heels, floors and stair climbing, squat toilet and prolonged squatting were not significantly associated with the prevalence of knee osteoarthritis. Conclusion There is a high prevalence of knee osteoarthritis in the elderly in Pudong New District in Shanghai, females have a higher prevalence of knee osteoarthritis than males, and the prevalence of knee osteoarthritis increases with age. Old age, female, overweight/obesity, a lot of housework, family history of osteoarthritis, knee trauma, cold environment, prolonged standing and walking are the risk factors for knee osteoarthritis.