Abstract: Objective　To investigate the related risk factors of thrombosis in patients with BCR/ABL negative myeloproliferative neoplasms(MPN) for clinic. Methods The JAK2V617F mutation of 104 patients with MPN was detected by allele-specific polymerase chain reaction (AS-PCR) method. Clinical features, laboratory examinations and thrombosis events of 104 patients with MPN were retrospectively studied.　Univariate analysis was applied on the pathologic information and multivariate analysis was applied based on the univariate analysis. Results Seventy-one cases of JAK2V617F mutation(68.3%) and 45 cases of thrombosis (43.3%) were identifi ed in 104 patients with MPN. Univariate analysis revealed that age, hypertension, diagnosis, JAK2V617F and WBC were correlated with thrombosis (P＜0.05). Multivariate analysis revealed that advanced age（≥60 years）, JAK2V617F mutation and increased WBC count were independent risk factors of thrombosis (P＜0.05). Conclusion　 The thrombosis risk for MPN patients with advanced age, JAK2V617F mutation or increased WBC count may suffer high risk of thrombosis.