Objective To observe the therapeutic effect of long round needle on knee osteoarthritis (KOA). Methods A total of 60 patients with KOA admitted to Beijing Hepingli Hospital from February 2020 to February 2021 were selected as research objects, and devided into the control group and the study group by the envelope method, with 30 patients in each group. Patients in the control group were treated with conservative treatment or joint cavity injection according to the results of the floating patella test, while the study group was treated with long circular needles to untie the knots at the transversal tendon lesion points on top of the control group. The scores of KOA severity, TCM evidence and Tegner knee motion were compared between the groups before and after treatment. Results Before treatment, there were no significant differences in KOA severity score, TCM syndrome score and Tegner knee motion score between the two groups (P＞0.05). After treatment, the scores of Tegner knee movement in the study group was higher than that in the control group, and the socores of KOA severity and TCM syndrome in the study group were lower than those in the control group, with statistically significant differences (P＜0.05). Conclusion The long round needle has a significant effect on knee osteoarthritis, and can improve the TCM syndrome and motor function of patients.