To provide experimental basis for clinic treatment by observing the effects of simple acute hematoma on cartilage and synovium, and improvement of hyaluronic acid (HA) on the damage. Twenty-four New Zealand white rabbits were randomly divided 3 groups according to killed time: hematoma group, HA group and control group. These rabbits were killed at 4 days, 2, 4 and 8 weeks, respectively. Knee articular cartilage and synovium were obtained to detect histology, histochemistry and chondroitin proteoglycans (PG). Morphologies of cartilage and synovium in the control group were normal, while cartilage cells were detected hyperplasia of activation and each layer was disorganized in hematoma groups with 4 days and 2 weeks. Compared to the control group, concentrations of PG in 4 days and 2 weeks groups were significantly reduced (p < 0.05), while no significant difference was detected between 4 weeks group and the control group. Morphology was recovered normal in 8 weeks. Compared to hematoma group, morphology and histochemistry were improved in HA group at each time frame. Simple acute hematoma can lead to temporary change of morphology and biochemistry. Application of HA can reduce damage of hemarthrosis on cartilaginous and shorten the cartilage recovery time.