Objective:To investigate the distribution and general pattern of TCM syndromes of knee osteoarthritis (KOA) among the middle-aged and elderly people in Shanghai community. MethodsThe middle-aged and elderly KOA patients were selected from 33 communities in 9 municipal districts of Shanghai from July 1,2016 to September 1,2018 by using the questionnaire of TCM syndromes of knee osteoarthritis. The general data, course of disease, local symptoms of knee joints, general symptoms, tongue and pulse conditions and X-ray findings of knee joints were collected and statistically analyzed by professional TCM orthopedists and traumatologists to determine TCM syndromes, and the correlation between TCM syndromes and age, sex, course of disease and X-ray grading was also analyzed.  Results:①A total of 1,990 KOA patients were included in the study, including 484 males and 1,506 females. The age ranged from 45 to 85 years old, with an average age of 66.0±5.8 years old. The course of disease lasted 1 to 480 months, and the median course of disease was 24 months. There were 702 cases of cold-dampness obstruction syndrome, 542 cases of liver and kidney deficiency syndrome, 406 cases of phlegm-stasis obstruction syndrome, 244 cases of qi and blood deficiency syndrome, and 96 cases of damp-heat blocking collaterals syndrome. According to the X-ray findings, 62 cases were classified as grade 0,265 cases as grade I, 628 cases as grade Ⅱ, 666 cases as grade Ⅲ and 369 cases as grade Ⅳ. ②There was a weak correlation between the distribution of KOA TCM syndromes and gender (χ,2,=118.8, P＜0.001, C=0.237). More women patients had cold-dampness obstruction syndrome and qi and blood deficiency syndrome, more men patients had damp-heat blocking collaterals syndrome, and the proportion of men and women in patients with phlegm-stasis obstruction syndrome and liver and kidney deficiency syndrome was equivalent. ③There was a weak correlation between the distribution of KOA TCM syndromes and age (χ,2,=361.3, P＜0.001, C=0.392). Patients with cold-dampness obstruction syndrome and phlegm-stasis obstruction syndrome were mostly aged between 55 and 75 years old. Patients with damp-heat blocking collaterals were mostly under 65 years old. Patients with liver and kidney deficiency syndrome and qi and blood deficiency syndrome were mostly over 55 years old. ④There was a weak correlation between the distribution of KOA TCM syndromes and disease course (χ,2,=190.7, P＜0.001, C=0.296). The disease course of patients with damp-heat blocking collaterals syndrome was mostly within 6 months, that of patients with cold-dampness obstruction syndrome and phlegm-stasis obstruction syndrome was mostly over 7 months, and that of patients with liver and kidney deficiency syndrome and qi and blood deficiency syndrome was often more than 24 months. ⑤There was a weak correlation between the distribution of KOA TCM syndromes and X-ray grading (χ,2,=544.1,P＜0.001, C=0.463). Based on the X-ray grading system, cold-dampness obstruction syndrome was mostly classified into grade I, Ⅱ and Ⅲ, damp-heat blocking collaterals syndrome was mostly classified into grade I and Ⅱ, liver and kidney deficiency syndrome and phlegm-stasis obstruction syndrome were mostly classified into grade Ⅲ and Ⅳ, and qi and blood deficiency syndrome was classified into grade Ⅱ and above.  Conclusion:TCM syndromes of knee osteoarthritis in the middle-aged and elderly people in Shanghai community were ranked from cold-dampness obstruction syndrome, liver and kidney deficiency syndrome, phlegm-stasis obstruction syndrome, qi and blood deficiency syndrome to damp-heat blocking collaterals syndrome in turn. Moreover, the distribution of KOA TCM syndromes has weak correlations with gender, age, course of disease and X-ray grading, which needs further study.