Objective:To investigate the analgesic effect of ultrasound-guided quadratus lumborum block at the lateral supra arcuate ligament (LSQLB) and subcostal transversus abdominis plane block (TAPB) for open liver surgery.Methods:Forty-two patients who underwent elective open liver surgery in Lishui Central Hospital from February 2021 to October 2021 were randomly divided into two groups: LSQLB group (L group, n=21) and TAPB group (T group, n=21). Both groups underwent preoperative ultrasound-guided nerve block, and then LSQLB in group L and subcostal TAPB under the right costal margin in group T. The surgery was subsequently completed under general anesthesia. Patient controlled intravenous analgesia (PCIA) was performed in both groups. The mean arterial pressure (MAP) and heart rate (HR) before skin cutting (T 0), immediately after skin cutting (T 1), at the time of liver exploration (T 2), and at the time of suturing (T 3) were compared between the two groups; the intraoperative sufentanil and remifentanil consumption was recorded; the visual analogue score (VAS) of pain at 2, 8, 16, 24, and 48 h postoperatively and the number of analgesic pump presses and remedial analgesia at 48 h postoperatively were recorded. The incidence of adverse effects such as postoperative hypotonia (lower limb muscle strength ≤grade 4 on the blocked side), hypotension, nausea and vomiting were recorded. Results:The MAP and HR at T 1, T 2 and T 3, the dosage of sufentanil and remifentanil during operation of group L were lower than those of group T(all P<0.05); the VAS score at 2, 8, 16 and 24 hours after operation in group L were lower than those of group T (all P<0.05). The number of analgesic pump presses and remedial analgesia at 48 hours postoperatively in group L were less than those in group T after operation (all P<0.05). There was no statistically significant difference in the incidence of adverse reactions such as postoperative hypokinesia, hypotension, nausea and vomiting in the two groups (all P>0.05). Conclusions:LSQLB for open liver surgery is more hemodynamically stable and has a more definite analgesic effect.