Hyaluronic acid (HA) which existsin large amounts in synovial fluid and joint cartilage, is a naturally found substance in human body. It plays an important role in normal joint function and shows qualitative and quantitative changes in osteoarthritis. In this review, during the degeneration process, which was performed with excising of anterior cruciate ligament (ACL) of rabbits’ knee joints, effects of intraarticular Sodium HA (NaHA) injection on joint cartilage is investigated. ACL of twenty rabbits were excised for this purpose and by the end of fourth week, ten of them were injected in their knees with 0.3 ml NaHA weekly and three times totally. The other ten, control group were injected with 0.3 ml saline solution with the same protocol. After four weeks by last injections, all rabbits were killed and joint cartilage were considered macroscopically and microscopically. In control group, fissuring and erosive changes of joint cartilage with an increase in fibrous tissue elements was observed. In which intraarticular NaHA injection group slight cartilage damage and evident chondroblast proliferation was observed.