〔Abstract〕 Objective To investigate the role of balance training in the rehabilitation of anterior cruciate ligament (ACL) injury after a knee reconstruction. Methods 60 patients who underwent ACL reconstruction surgery in Zengcheng District of Xintang Hospital Guangzhou from February 2019 to February 2020 were selected and divided into an observation group and a control group using the random number table method, with 30 patients in each group. Patients in the control group received conventional rehabilitation training after surgery, while the observation group received balance training based on the control group. 12 weeks later, the balance and functional recovery of the knee joint in the two groups were compared, and the satisfaction of patients in the two groups was counted. Results After treatment, the trajectory length index (LFS) for the center of pressure X/Y axis, ellipse area covering 90%, and functional surface area with eyes open and closed in the observation group were significantly lower than those in the control group, with statistically significant differences (P < 0.05). Before treatment, there were no statistically significant differences in the Lysholm Knee Function Scale (LKSS) scores between the two groups (P > 0.05). After treatment, the LKSS scores in both groups were significantly higher than that before treatment, and the difference was statistically significant in the observation group compared to the control group (P < 0.05). The satisfaction rate of patients in the observation group was 93.33%, which was significantly higher than that of the control group (66.67%), and the difference was statistically significant (P < 0.05). Conclusion The application of balance training in post-operative rehabilitation of ACL injury reconstruction can significantly promote the recovery of patient's knee function and balance ability, improve patient satisfaction.