Abstract: 【Abstract】Objectives: To investigate the expression and significance of VEGF and endoglin of synovial tissues in rats induced by Ⅱcollagen. Methods: The experimental arthritis model was established by subcutaneous injection ofⅡcollagen. Morphological changes were found through observing the secondary paw swelling and histological morphological of synovial tissues in rats. The expression of VEGF and endoglin protein was detected through immunohistochemistry and RT-PCR techniques. Results: Most arthritis take place in 2~3 weeks after collagen injection. The sympotom includes such as: swelling of the paws and limited movement of joint. The expression of VEGF and endoglin was higher in the synovium of CIA than that of normal rats（p<0.05）. There was a strong positive relationship between VEGF and endoglin,( p<0.05）.Conclusions: They were involved in the pathogenesis of RA. VEGF and endoglin play impotent roles in RA response and in the cytokine web of new synovium vascularization, VEGF and endoglin affect and promote those of each other , and may regulate the vicious web circulation. They were the keys of many cytokines that mediate RA pathogenesis, development, invading, and joint deformation.