[Objective] To explore the effect of the degree of knee inversion deformity on total knee arthroplasty (TKA). [Methods] A total of 86 patients with osteoarthritis of the knee who underwent TKA in our hospital were selected and divided into mild group (≤10°) and moderate group (10°~20°) according to the degree of deformity of the patients. Perioperative data, follow-up results and imaging findings were compared between the two groups, and the correlation between lower extremity force lines and clinical scores was analyzed. [Results] There was no significant difference in the comparison of operation time, incision length, intraoperative blood loss, postoperative drainage, time to walk on the ground, incision healing grade, hospitalization time, and treatment cost between the two groups (P>0.05). Over time, postoperative VAS score and WOMAC score decreased significantly in both groups, while knee extension-flexion ROM and HSS score increased significantly (P<0.05). Preoperative knee extension-flexion ROM, HSS score, VAS score, and WOMAC score were significantly different between the two groups (P<0.05). At three months postoperatively, VAS score, WOMAC score, knee extension-flexion ROM, and HSS score were better in the mild group than in the moderate group (P<0.05). At the final follow-up, there was no statistical significance of the above indexes in both groups (P>0.05). In terms of imaging, there were significant differences in preoperative FTA, MPTA, PTS, and MAD between the two groups, and at the final follow-up of the two groups, FTA and MPTA were significantly improved compared with the preoperative period, with a significant difference in comparison between the groups (P<0.05), and there were no significant changes in PTS and MAD compared with the preoperative period, with no significant difference in comparison between the groups (P>0.05). [Conclusion] Different degree of knee inversion deformity significantly affected the lower limb force line after TKA, but had no significant effect on knee mobility and knee function.