Abstract：Objective：To observe the curative effect of ultramicro needle-knife for senile knee osteoarthritis(KOA) and its effect on Lysholm scores of knee， inflammatory factors and quality of life. Methods：A total of 74 cases of senile patients with KOA were given a retrospective analysis on their clinical data， and were divided into the treatment group and the control group according to their treatment methods， 37 cases in each group. The control group was treated with Chinese medicine decoction， and the treatment group was additionally treated with ultramicro needle- knife based on the treatment of the control group. Before and after treatment， the changes in scores of Lysholm， Visual Analogue Scale(VAS)， Western Ontario and Mcmaster Universities Osteoarthritis Index(WOMAC) and 36-Item Short Form Health Survey(SF- 36) as well as levels of interleukin-1(IL-1)， tumor necrosis factor-α(TNF-α) and prostaglandin E2(PGE2) in the two groups were detected. The clinical effects and the incidences of adverse reactions in the two groups were compared. Results：The total effective rate was 94.59% in the treatment group， higher than that of 75.68% in the control group(P＜0.05). After treatment， the scores of VAS and WOMAC as well as the levels of IL- 1， TNF- α and PGE2 in the two groups were decreased when compared with those before treatment(P＜0.05)， and the scores of Lysholm and SF- 36 were increased(P＜0.05)； the scores of VAS and WOMAC as well as the levels of IL-1， TNF-α and PGE2 in the treatment group were lower than those in the control group(P＜0.05)， and the scores of Lysholm and SF-36 were higher(P＜0.05). There was no significant difference being found in the comparison of the adverse reactions between the two groups(P＞0.05). Conclusion：Ultramicro needle- knife for senile KOA has a significant clinical effect， and can effectively relieve pain， improve knee joint activity and function， reduce inflammatory responses， and enhance quality of life with good safety.