OBJECTIVE: To explore the expression of EVI1 gene in AML and the ALL patients' bone marrow cells, and its correlation with the leukemic typing, clinical characteristics and prognosis. METHODS: Three hundred and thirty-three cases of leukemia in our hospital from 2012 to 2016 were enrolled in this study. Among them there were 263 cases of AML, 70 cases of ALL, and 13 volunteers were selected as normal controls. The bone marrow samples of the patients and volunteers were aspirated. Firstly, the blood mononuclear cells(PBMNC) were separated from the samples through the Ficoll-Hypaque density gradient centrifugation. Secondly, the total DNA was extracted, and the expression of EVI1 mRNA were assayed by real-ime quantitative PCR, which help to find out the EVI1 mRNA expression difference between AML and ALL. Finally, the correlation of EVI1 expression with the acute leukemia typing, clinical characteristics and prognosis were analyzed by a series of statistical method. RESULTS: Based on the expression levels of the EVI1 mRNA determined by real-time quantitative PCR, the expression levels in AML and ALL were both higher, but without significant difference. The rates of both EVI1 mRNA overexpression and low expression of the EVI1 mRNA in AML patients were higher than those in AML group, however, the rate of normal expression in ALL group was statistically significantly lower than that in the AML. The level of Plt in patients with AML-M1 and T-ALL positively correlated with the level of EVI1 expression（r=0.393,P<0.05；ρ=0.442，P<0.05）while the level of blasts(%) in patients with AML-M3 negatively correlated with the level of EVI1 expression. The expression of EVI1 correlated with the age of patients（χ2 =6.684,P<0.05）. The prognosis of AML patients with high expression of EVI1 mRNA was poor（Log-Rank test，P<0.05）and AML-M3 patients with high expression of EVI1 had a significantly poorer prognosis than that of patients without high expression（Log-Rank test，P<0.01）. CONCLUSION: In expression level of EVI1 no difference has been found in AML and ALL, but the distribution of EVI1 expression shows obvious difference and the difference correlats with the age of patients, at the same time, the some clinical features and subtype of acute leukemia correlate with the expression level of EVI1.