Objective To investigate the diagnostic value of JAK2V617F mutation detection in the diagnosis of polycythemia vera,and screen a more simple method for clinic laboratory to detect the mutation of JAK2V617F.Method DNA was extracted by standard procedures after isolating total leukocytes from peripheral blood mononuclear cells by density gradient centrifugation over Histopaque 1077.DNA samples were amplified,and single-stranded biotinylated PCR products were prepared for sequencing.At the same time,in order to testify the reliability of the allele-specific PCR,two forward primer and one common reverse primers were applied for identifying the mutation.Result In 32 of 38 patients with polycythemia vera,JAK2V617F mutation was determined by conventional DNA sequencing.35 JAK2V617F mutations were detected by the allele-specific PCR.and these mutations were confirmed by DNA sequencing.None mutation was found in secondary polycythemia and normal control.Conclusion JAK2V617F function mutation occuis in nearly all patients with PV,and JAK2V617F mutation should be a molecular marker in the diagnosis of polycythemia vera.Allele-specific PCR is a very sensitive and specific method for detecting JAK2V617F mutation.