Objective: It remains unclear whether Tai Chi is effective for walking function and posture control improvements in aged populations with knee osteoarthritis. The aim of this study was to systematically evaluate the effects of Tai Chi on improving walking function and posture control in elderly patients with knee osteoarthritis by updating the latest trial evidence. Methods: Web of Science, PubMed/Medline, Embase, Scopus, PEDro, and Cochrane library were searched up to October 1, 2020 to identify RCTs evaluating Tai Chi for improving walking function and posture control in older adults with knee osteoarthritis. The primary outcomes were walking function and posture control. Meta-analysis was performed with RevMan Version 5.3 software. Results: A total of 603 participants with knee osteoarthritis in the 11 trials were included. The results of meta-analysis showed that: The Tai Chi group was associated with better performance in 6-minute walk test (6 MWT), time up and go test (TUG) and “Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index” Physical Function Score than the control group ([MD: 46.67, 95% CI 36.91–56.43, P < .001]), ([MD: −0.89, 95% CI −1.16 to −0.61, P < .001]), ([MD: −11.28, 95% CI −13.33 to −9.24, P < .001]). Conclusion: This meta-analysis provided evidence from 11 RCTs that Tai Chi could be an excellent physical training strategy for improving walking function and posture control in older adults with knee osteoarthritis. Assuming that Tai Chi is at least effective and safe in most areas, it can be used as an adjuvant and reliable physical training strategy for walking function upgrading and balance control improvements for older patients with knee osteoarthritis.