Abstract: Objective To investigate the applicability of sodium hyaluronate（SH） intra-anticular injection in treatment of knee osteoarthritis（KOA） by observing its therapeutic effect on KOA at different degrees.Methods One hundred and eighteen patients with KOA（145 knees） were divided into excellent,good,moderate and poor outcome groups according to the hospital for special surgery（HSS） score for their knees and treated with SH intra-articular injection.Their knees were scored with the HSS scoring system 3,6 and 12 months before and after treatment,respectively.Results The HSS score was significantly higher in excellent and good outcome groups 3,6 and 12 months after treatment than before treatment（P＜0.05）.No statistical difference in HSS score was observed between the moderate and poor outcome groups before and after treatment（P＞0.05）.Conclusion SH intra-articular injection has a rather good effect on mild and moderate KOA but has no statistical effect on severe KOA.