AIM: To investigate the involvement of HIF-1α/VEGF regulation in its anti-angiogenesis effects using adjuvant-induced arthritis (AIA) rats. METHODS: AIA rats were orally treated by QLY extract for 24 days. After sacrifice, the joints were subjected to histological examination, while the blood was used in ELISA or biochemical tests. In addition, HUVEC cells were treated by QLY in vitro. MTT, wound-healing and tube-formation experiments were then  performed. Expression of some relevant proteins in cells were investigated.RESULTS: Compared to the healthy controls, obvious synovial invasion and angiogenesis occurred in AIA rats. Blood levels of HIF-1ɑ, VEGF, PDGF, and TGF-β1 were increased, while the ratio of MDA/SOD was decreased a lot. After QLY treatment, all these abnormalities were attenuated. In vitro experiments, QLY showed notable potentials in inhibiting proliferation, migration and tube-constructing abilities of HUVEC cells. Furthermore, it suppressed the expression of p-MEK/MEK and p-ERK/ERK. CONCLUSION: QLY can reduce the pathological functions of vascular endothelial cells by inhibiting HIF-1α/VEGF, and it consequently eased AIA-related abnormal angiogenesis in AIA rats' joints.