Objective To evaluate the application of short-term preoperative blood flow restriction training (BFRT) in elderly patients undergoing total knee arthroplasty (TKA). Methods Elderly patients undergoing primary unilateral TKA for knee osteoarthritis admitted to China-Japan Friendship Hospital, Jilin University between January and June 2025 were prospectively enrolled and randomly divided into the trial group and the control group at a ratio of 1∶1. Patients in the control group received routine perioperative treatment, nursing care and postoperative continuous passive motion training. On this basis, the trial group received short-term preoperative BFRT. Feasibility, adherence and safety indicators were observed. The 30-second Chair Stand Test (30s-CST) was used to assess lower extremity function, and linear mixed-effects models were applied to analyze functional changes. Results A total of 185 patients were screened, among whom 160 were enrolled, yielding a recruitment rate of 86.49%. A total of 153 patients completed all follow-ups, with a follow-up completion rate of 95.63%. The training adherence rate in the trial group was 99.17%, 95.00% of patients finished all 6 training sessions, and no participants withdrew from the study due to poor adherence. There were no statistically significant differences in baseline characteristics or the overall incidence of adverse events between the two groups (P＞0.05). No deep vein thrombosis, pulmonary embolism or other serious adverse events occurred in either group during the study period. A total of 8 mild adverse events were reported in the trial group, all of which resolved spontaneously after rest or adjustment of training parameters. Linear mixed-effects model analysis revealed statistically significant between-group effect, time effect, and group-by-time interaction effect for the number of 30s-CST repetitions (P<0.05). Conclusions Short-term preoperative BFRT has good feasibility, compliance and short-term safety in elderly patients undergoing TKA, and preliminarily shows a potential effect in promoting the recovery of postoperative lower limb function. It can serve as a potential supplementary approach for perioperative prehabilitation.