Objective To evaluate the modifying efficacy of quadratus lumborum block ( QLB ) combined with general anesthesia in the patients undergoing percutaneous nephrolithotomy ( PCNL) . Meth-ods Sixty American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients, aged 33-64 yr, with body mass index of 18-27 kg∕m2 , scheduled for elective PCNL with general anesthesia, were divided into general anesthesia group ( group GA) and QLB combined with general anesthesia group ( group QLB+GA) , with 30 patients in each group. In group QLB+GA, the anterior approach to QLB was performed with 0. 357％ ropivacaine 20 ml on the side of operation under the ultrasound guidance before induction of anes-thesia. Anesthesia was induced with IV midazolam, propofol, sufentanil and cisatracurium. Anesthesia was maintained by intravenously infusing propofol, remifentanil and cisatracurium. Patient-controlled intra-venous analgesia ( PCIA) was performed at the end of operation. PCIA solution contained sufentanil 2μg∕kg in 100 ml of normal saline. The PCA pump was set up with a 2 ml bolus dose, a 15-min lockout in-terval, and background infusion at a rate of 2 ml∕h. Numeric rating scale score was maintained ≤ 3 after operation. When numeric rating scale score ≥4, flurbiprofen axetil 50 mg was intravenously injected as rescue analgesic. The intraoperative consumption of propofol and remifentanil, occurrence of adverse reac-tions ( nausea and vomiting, agitation, respiratory depression, somnolence) in postanesthesia care unit, consumption of sufentanil for PCIA within 48 h after operation, the number of successfully delivered doses, requirement for rescue analgesics, recovery time of intestinal exhaust gas, and length of postoperative hos-pital stay were recorded. Results Compared with group GA, the intraoperative consumption of propofol and remifentanil was significantly reduced, the rate of rescue analgesia, consumption of sufentanil for PCIA within 48 h after operation and the number of successfully delivered doses were decreased, the incidence of agitation, respiratory depression and somnolence in postanesthesia care unit was decreased, and the recov-ery time of intestinal exhaust gas and length of postoperative hospital stay were shortened in group QLB+GA ( P<0. 05) . Conclusion QLB combined with general anesthesia is helpful in carrying out the anesthetic model of low-consumption opioids and more helpful in inhibiting postoperative pain responses and promoting postoperative recovery than general anesthesia alone in patients undergoing PCNL.