Abstract: OBJECTIVE To discuss the distribution of pathogenic bacteria and related risk factors affecting delayed infection after total knee arthroplasty(TKA), so as to provide references for clinical treatment. METHODS The clinical data of 500 cases of patients treated with TKA in our hospital from Jan. 2010 to Mar. 2015 were retrospectively analyzed. The distribution of pathogenic bacteria and the risk factors of patients with delayed infection were analyzed. The data were analyzed by SPSS 20.0. RESULTS There were 30 cases of patients occurred nosocomial infection in the 500 cases after TKA, with the infection rate of 6.00%, and there were 7 cases of patients who happened delayed infection. A total of 11 strains of pathogenic bacteria were detected, and mainly were 6 strains of gram-positive bacteria, accounting for 54.55%. The multivariate analysis showed factors such as age, smoking, operation time, diabetes mellitus, and postoperative wound drainage were the independent risk factors for delayed infection after TKA (P<0.05). CONCLUSION There are many risk factors for delayed infection after TKA, which should be focused on to prevent on the basis of strict aseptic operation in hospital, so as to minimize the incidence of delayed infection.