Abstract: Objective To investigate the influence of interferon-alpha-2b (IFN-α2b) with JAK2 kinase,COX-2 and microvessel density in patients of MPN and the relation of JAK2V617F and COX-2 in human erythroleukemia cell line (HEL) cells. Methods Forty-two cases of MPN patients with JAK2V617F mutation of initial treatment were collected from the Frist hospital of Baoding,including the IFN-α2b treatment group with 17 cases and untreated group with 25 cases. 10 cases of idiopathic immune thrombocytopenic purpura (ITP) patients synchronization were enrolled as controls. JAK2V617F/JAK2 mutation burden of MPN patients was detected by real time PCR (qRT-PCR);the expression levels of p-JAK2, COX-2 and microvascular density (MVD) marked with CD105 inpathological tissues of bone marrow in patients of MPN and ITP were detected by immunohistochemistry. The HEL cells were treated with different concentrations of IFN-α2b. The cell proliferation inhibition rate was calculated by CCK-8 test;the apoptosis rate was detected by flow cytometry; cell migration ability was tested by transwell chambers. JAK2 and COX-2 mRNA were detected by semi-quantitative PCR; p-JAK2 and COX-2 protein in HEL cells were detected by Western blotting.Results The expression levels of p-JAK2,COX-2 protein and MVD in untreated group were significantly higher than those of control groups. p-JAK2,COX-2 and MVD levels were significantly reduced in patients treated with IFN-α2b. Cell growth inhibition rates and apoptosis rates raise up by dose of IFN-α2b in HEL cells at 48 h.The mRNA expression levels of JAK2 and COX-2 as well as protein expression levels of p-JAK2 and COX-2 had a decreasing tendency with the increase of IFN-α2b concentration at 48 h.The migration capacity level of HEL cells which treated with 0.5×10 4 U/L IFN-α2b after 24 h was lower than that of control group. Conclusion Angiogenesis of MPN and COX-2 were inhibited by IFN-α2b which regulates JAK2 signal pathway.