Objective To determine the impact of the lower limb weight-bearing line ratio (WBLR) on motor function recovery after high tibial osteotomy (HTO). Methods A retrospective analysis was conducted on 55 patients with unilateral compartment knee osteoarthritis who underwent open-wedge HTO between August 2020 and October 2023 and met the selection criteria. Based on the postoperative Lysholm score, patients were divided into two groups: the good knee function group (Lysholm score≥90, group A) and the poor knee function group (Lysholm score<90, group B). Lysholm score, American Knee Society (AKS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and visual analogue scale (VAS) score for pain were compared between the two groups. Univariate analysis was performed on baseline data including gender, age, body mass index (BMI), affected side, disease duration, Kellgren-Lawrence grade, and radiographic parameters including preoperative and postoperative medial proximal tibial angle, lateral distal femoral angle, femorotibial angle, hip-knee-ankle angle (HKA), WBLR, posterior tibial slope angle, and joint line convergence angle to identify factors influencing functional recovery. Multivariate logistic regression analysis was further used to identify independent factors. Additionally, receiver operating characteristic (ROC) curve analysis was employed to determine the optimal cut-off value of postoperative WBLR for predicting motor function recovery, and the area under curve (AUC) was calculated to assess diagnostic performance. Results All 55 patients were followed up 10-14 months (mean, 11.8 months). According to the postoperative Lysholm score, there were 30 patients in group A and 25 in group B. All postoperative clinical scores in group A were significantly better than those in group B (P<0.05). Univariate analysis indicated that age, BMI, postoperative HKA, and postoperative WBLR were influencing factors for motor function recovery (P<0.1). Further multivariate logistic regression analysis identified a postoperative WBLR≤55.5% as an independent factor influencing motor function recovery (P<0.05). ROC curve analysis yielded an AUC of 0.788 and determined the optimal postoperative WBLR cut-off value for predicting motor function recovery to be 55.5% (P<0.001).Conclusion A postoperative WBLR of 55.5% is associated with optimal motor function recovery after HTO.