Objective To investigate the frequency of JAK2 V617F mutation and JAK2 V617F mutation allele burden in patients with essential thrombocythemia (ET), and explore the relationship between mutation and hematological parameters and coagulation function. Methods The clinical and laboratory parameters of 90 ET patients were analyzed. JAK2 V617F mutation was detected by AS-PCR and the mutation allele burden of JAK2 V617F was detected by qPCR. The correlation between mutation frequency and mutation burden of JAK2 V617F and blood laboratory parameters were investigated in ET. Results JAK2 V617F mutation was found in 50 patients (55.6 %). RBC [(4.67±0.89)×109/L vs (4.04±0.99)×109/L, P =0.003], WBC (11.64±5.20)×109/L vs (9.11±4.11)×109/L, P = 0.014], HCT (0.41±0.07) vs (0.36±0.07), P =0.005) in the JAK2 V617F mutated group were higher than those in the wild-type group. PT in mutated patients was longer than that in wild-type group [(13.18±1.63) s vs (12.02±1.24) s, P = 0.000]. The JAK2 V617F mutation allele burden was (29.91 ±18.63) %. No significant correlation was found between JAK2 V617F mutation allele burden and hematological parameters such as WBC, RBC and Plt (all P>0.05), but the JAK2 V617F mutation allele burden had a significant correlation with FDP (r = 0.456, P = 0.001). Conclusions JAK2 V617F mutation occurs in significant percentage patients with ET. Detection of JAK2 V617F mutation allele burden at diagnosis may play an important role in the early prevention of vascular events.