To observe the therapeutic effect of Jinteng Qingbi Granule on synovial angiogenesis in collagen-induced arthritis(CIA) rats and explore its mechanism.Methods:Sixty SD rats were randomly divided into blank group，model group，methotrexate group，and Jinteng Qingbi Granule low-，medium-and high-dose groups.The CIA rat model was established by immune induction，once a day.The rats in blank group andmodel group were given the same amount of normal saline by gavage once a day for 28 days.Small animal ultrasound imaging was used to detect the synovial hyperplasia score and hyperplasia area in the knee joint of the right lower limb of rats in each group.The serum IL-6，IL-17 and TNF-α were detected by ELISA.HE staining was used to observe the pathological changes of synovium in rats.The expressions of CD31 and VEGFR2 in synovial tissue of rats were determined by IHC.Results:Compared with the conditions in blank group，the synovial area and synovial hyperplasia score of CIA rats in model group were increased(P<0.01); significant pathological changes were also observed in the synovium of rat joints; serum inflammatory factors were up-regulated，and CD31 and VEGFR2 were also increased(P<0.01).Compared with model group，Jinteng Qingbi Granule groups had reduced synovial hyperplasia area in CIA rats(P<0.01); Jinteng Qingbi Granule high-dose group had decreased synovial score(P<0.01); Jinteng Qingbi Granule medium-and high-dose groups improved the pathological changes of synovial tissue of rats，reduced IL-6，IL-17 and TNF-α(P<0.01)，and lowered CD31 and VEGFR2 in synovial tissue of joints(P<0.01).Conclusion:Jinteng Qingbi Granule can inhibit the pathological progress of rheumatoid arthritis by improving the synovial angiogenesis of CIA rats，thereby reducing the joint damage.The mechanism may be related to inhibiting the secretion of inflammatory factors and down-regulating CD31 and VEGFR2.