To evaluate the efficacy and safety of interferon-alpha-2b (IFN-α-2b) in polycythemia vera patients(PV patient) with or without post-polycythemic myelofibrosis (post-PV MF), 30 patients with mutated JAK2V617F were enrolled in this study, from which 29 patients were evaluable. The percentage of mutated JAK2V617F allele (V617F%) was evaluated by real-time polymerase chain reaction (RT-PCR) before and after treatment with IFN-α-2b. The correlation of V617F allele burden with the major clinical outcomes was studied. Adverse effects appeared in patients was observed. The results showed that the median follow-up was 24 (12 - 42) months for 29 evaluable patients. Complete hematologic response was achieved in 10%, 48%, 72% and 78% of patients after treatment for 6, 12, 24 and 36 months respectively. The detection of V617F allele burden revealed that the molecular remission of patients (V617F%) was achieved in 41%, 76%, 89% and 89% after treatment for 6, 12, 24 and 36 months respectively. Molecular complete remission (JAK2V617F undetectable) was achieved in 4 patients, lasted from 6 to 12 months after IFN-α-2b discontinuation. The decrease of V617F% in patients with post-PV MF was significantly higher than that in patients without post-PV MF (53 ± 18% vs 32 ± 22%, respectively; p = 0.031) after treatment for 12 months. PV patients had a good tolerance to IFN-α-2b. It is concluded that IFN-α-2b can decrease the mutated V617F allele burden. Patients with PV, especially with post-PV MF, can achieve molecular remission after treatment with IFN-α-2b.