In order to explore the influence of sodium hyaluronate on knee osteoarthritis (KOA) patients synovial fluid interleukin -1β (IL-1β) and analyze its clinical mechanism, this study analyzed 40 cases of KOA patients in our hospital's orthopaedic department, randomly divided them into two groups: Sodium hyaluronate group (group A) and normal saline group (group B), each consists 20 patients. Besides, we selected another 20 patients as normal control group. Group A treated knee joint cavity by injecting sodium hyaluronate, and group B injected knee joint cavity in equal amount of normal saline, once a week for five weeks. Collect respectively knee joint synovial fluid in patients of group A and group B before treatment and after five weeks of treatment, detect the content of knee joint synovial fluid IL-1βin of all the three groups by using enzyme linked immunosorbent assay (ELISA). We can conclude that (1) IL-1β content of knee joint synovial fluid in KOA patients before treatment was significantly higher than healthy people; (2) IL-1β content of group A knee joint synovial fluid after treatment was significantly reduced than before treatment, there was no significant difference for group BIL-1β content before and after treatment; (3) there was no significant difference between group A knee joint synovial fluid IL-1β content after treatment and healthy people. Thus it can be proved that content of IL-1β in knee joint synovial fluid KOA patients is higher than healthy people; sodium hyaluronate can reduce the content of IL-1β in synovial joints and can be effective in the treatment of knee osteoarthritis.