Abstract: Objective Self-efficacy is the belief of the patient to complete the relevant target, and the effect of self-efficacy is very important for the recovery of knee joint function in patients undergoing knee replacement. The aim of this paper is to investigate the influence factors of postoperative self-efficacy in elderly patients with knee arthroplasty. Methods According to SER scores, A total of 92 elderly patients with knee arthroplasty in our hospital between January, 2014 and December, 2015 were enrolled and divided into pass group (52 cases) and fail group (40 cases) according to the Self-Efficacy for Rehabilitation Outcome Scale (SER). The anxiety scores, depression scores and social support scores were compared between the two groups. The risk factors of self-efficacy in elderly patients with knee arthroplasty were analyzed. Results The age of patients in the pass group was significantly lower than that in the fail group (t=-2.325, P=0.022), cultural degree and per capita monthly income of the pass group was significantly higher than those in the fail group (Z=-2.070, -2.274; P=0.038, 0.023); Anxiety scores and depression scores were significantly lower than those in the fail group (t=-6.972, -6.142; P<0.001), and social support scores was significantly higher than that in the fail group (t=8.683, P<0.001); Binary Logistic multi-factor regression analysis showed that age, anxiety and social support were the independent risk factors for the self-efficacy in elderly patients with knee arthroplasty. Conclusion The elderly patients with knee arthroplasty are usually with a low level of postoperative self-efficacy.The age, anxiety and social support are the independent risk factors of self-efficacy. Some targeted nursing program should be formulated to standardize the nursing care and strengthen the postoperative rehabilitation education, so as to improve the self-efficacy of patients.