Objective To screen the risk factors of postoperative blood transfusion in elderly patients undergoing unilateral hip surgery. Methods A retrospective study was conducted and 959 consecutive patients (aged≥65 years) undergoing unilateral hip surgery at Nanjing Drum Tower Hospital from June 2013 to May 2019 were enrolled. In order to identify the independent risk factors of postoperative blood transfusion, this study collected patients' basic information, co‑existing diseases, types of operation, intraoperative medication, intraoperative monitoring method, postoperative blood transfusion and other information to perform single factor analysis and multiple logistic regression analysis. Results A total of 109 patients (11.4%) received blood transfusion. Preoperative anemia (P<0.01)， hip revision operation (P=0.010) and amount of intraoperative blood loss≥6.67 ml/kg (P<0.01) were the independent risk factors of postoperative blood transfusion in elderly patients undergoing unilateral hip surgery. When using tranexamic acid during operation (P<0.01) , intraoperative temperature monitoring (P=0.027) were the protective factors. Conclusions Actively correcting preoperative anemia, using tranexamic acid during operation, and paying extensive attention to intraoperative temperature management may effectively reduce the incidence of postoperative allogenic blood transfusion after unilateral hip surgery in elderly patients. Thus, they are beneficial to avoid or reduce the occurrence of allogenic transfusion‑related complications, and shorten the length of stay.