Objective: To evaluate the effect of ultrasound-guided adductor canal block in postoperative pain management after open wedge high tibial osteotomy Methods: Sixty patients who underwent unilateral open wedge high tibial osteotomy were included in the study. All of the patients were randomly divided into experimental group (n = 30) and control group (n = 30). The VAS scores of the two groups were recorded at 6 h, 12 h, 24 h, 48 h and 72 h post operation, and the VAS scores of dynamic pain in the operation area were recorded at 48 h and 72 h after operation. The frequency of use of pethidine hydrochloric acid, the occurrence of adverse reactions and complications were recorded in the two groups. The complications such as exudation and extubation were recorded in the experimental group. Results: The VAS scores of kinetic pain at 6 h, 12 h, 24 h, 48 h and 72 h post operation in the experimental group were lower than those in the control group, but there was no significant difference in kinetic pain and dynamic pain between the two groups at 72 h post operation. The difference of VAS score in other periods was statistically significant. The frequency of pethidine hydrochloric acid in the experimental group was less than that in the control group. Three patients in the experimental group had fractures at the lateral hinge of the osteotomy line, while 2 patients in the control group had fractures of type I. Wound exudation occurred in 1 patient in the experimental group and 1 patient in the control group. There was no extubation in the experimental group. Conclusions: Ultrasound-guided adductor canal block showed a significant effect on pain management and can reduce the frequency of pethidine hydrochloric acid after open wedge high tibia osteotomy. There was no increase in adverse reactions and complications. Key words: Knee; Osteoarthritis ; High tibial osteotomy; Adductor canal block