Abstract: Objective To investigate the effect of Ruxolitinib on the expression of vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1 alpha (HIF-1α) in HEL cells. Methods The HEL cells were treated with Ruxolitinib in different concentrations (1 nmol/L, 5 nmol/L, 10 nmol/L, 50 nmol/L, 100 nmol/L, 500 nmol/L). The growth inhibition of Ruxolitinib on HEL cells was detected by CCK-8 assay; the mRNA expression level ofJAK2 were measured by RT-PCR and the protein level of p-JAK2, VEGF, HIF-1α were observed by Western blot after treated with Ruxolitinib for 24, 48, 72 h. Chick chorioallantoic membrane (CAM) test was used to testify the effect of Ruxolitinib on angiogenesis. Results Ruxolitinib with different concentrations could inhibit HEL cells proliferation. RT-PCR showed that the mRNA level ofJAK2 decreased in a concentration-dependent manner and Western blot demonstrated that the expression levels of p-JAK2, VEGF and HIF-1α were lower in Ruxolitinib treatment groups than those in control group (P <0.05) after HEL cells were treated with different concentrations of Ruxolitinib for 24, 48, 72 h. Ruxolitinib significantly suppressed blood vessels’ formation in CAM. Conclusion Ruxolitinib can inhibit VEGF, HIF-1α expression and angiogenesis of HEL leukemia cells by inhibiting JAK2 pathway.