Objective To observe the safety and effectiveness of ultrasound?guided femoral nerve combined with femoral artery block to reduce tourniquet reaction in patients undergoing knee arthroplasty. Methods 100 patients（18 ~ 75 years old， body mass index 18 ~ 30 kg/m²）who were classified as grade Ⅰ?Ⅲ according to ASA standard and received unilateral total knee arthroplasty. The patients were randomly divided into two groups，the ultrasound?guided femoral nerve combined with femoral artery block with general anesthesia was utilized in group NA with 50 cases， and femoral nerve block alone with general anesthesia was used in group N with 50 cases. The target nerve block was guided by ultrasound before induction of anesthesia in both two groups，and anesthesia induction was performed after the block effect was etermined. Patients in two groups underwent surgery under general anesthesia of the laryngeal mask，and all patients under went self?controlled intravenous analgesia（PCIA）. If a patient had a visual analogue score（VAS）score > 5 after surgery， flurbiprofenate 50 mg will be given intravenously as a remedy for analgesia. The patients' SBP，DBP and HR were recorded before anesthesia （T₁）， 1 min before tourniquet inflation （T₂）， 15 min after tourniquet inflation （T₃）， 30 min （T₄）， 45 min （T₅）， and 60 min （T₆），the number of cases of tourniquet hypertension occurring in patients intraoperatively and the amount of nicardipine and esmolol were recorded， and the movement and static VAS scores at 2， 6， 12， and 24 h after surgery were recorded.the postoperative rescue analgesic requirements and the time of getting out of bed were recorded. The incidence of adverse reactions such as nausea，vomiting，deliriumand infection were also recorded. Results Compared with group N，SBP，DBP and HR were significantly lower in group NA at 45 and 60 min after tourniquet inflation， and the incidence of tourniquet hypertension and the amount of nicardipine and esmolol were also significantly lower （P < 0.05）， and the time of getting out of bed was advanced （P < 0.05）； the movement and static VAS scores，the time of the first remedial analgesia， and number of times of remedial analgesia， as well as the occurrence of nausea，vomiting，delirium and infection were not statistically significant. Conclusion Ultrasound?guided femoral nerve combined with femoral artery block can be safely and effectively used to reduce the reaction of tourniquet in patients with knee arthroplasty， and can shorten the time of getting out of bed after surgery， contributing to promoting postoperative rehabilitation.