Objective: To investigate the effect of active body temperature protection on coagulation function and bleeding in patients with lower extremity fracture surgery. Methods: A total of 104 patients with elective open reduction and internal fixation of lower extremity fractures admitted to Jiangyin Hospital of Traditional Chinese Medicine from October 2019 to October 2021 were selected and randomly divided into two groups, 52 cases in each group. The control group only covered the chest and abdomen with a surgical towel, the room temperature was set to 22 ℃, and the room temperature liquid was infused and rinsed; the observation group was covered with a 3M inflatable thermal blanket to cover the chest and abdomen, and the skin was separated with a surgical towel, and the target body temperature was set at 38 ℃. The room temperature was set to 26 ℃ before surgery and 22 ℃ at the beginning of the operation, and 37 ℃ was used for liquid infusion and flushing. The ear temperature, R value, K value, maximum amplitude (MA) level, intraoperative blood loss, 24-h drainage volume, extubation time, first ambulation time, hospital stay, coagulation function before and after surgery, and postoperative complications were compared between the two groups at each time point rate situation. Results: The ear temperature of the observation group was higher than that of the control group at 1 hour after the operation and 1 hour after the operation (P<0.05). Compared with the control group (P<0.05); the intraoperative blood loss and 24-h drainage volume of the observation group were lower than those of the control group, and the extubation time, the first time to get out of bed, and the length of hospital stay were shorter than those of the control group (P<0.05); the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) of the observation group were higher than those of the control group, and fibrinogen (Fbg) was lower than that of the control group (P<0.05); there was no significant difference in the incidence of postoperative complications between the observation group and the control group (P>0.05). Conclusion: Active body temperature protection can improve body temperature and coagulation function in patients with lower extremity fracture surgery, reduce intraoperative blood loss and 24-h drainage volume, and has fewer complications and is safe and reliable.