Results and conclusion: median age at diagnosis was 56, female accounted for more than male, 16.1% of patients had history or manifestation of thrombosis at the time of diagnosis, 33.9% of patients were in high-risk group according to revised IPSET thrombosis; median platelet count was 1264 G / l; JAK2 V617F, CALR and MPL mutation were 55.7%, 19.1% and 2.6%, respectively.