MicroRNAs (miRNAs) are of great importance in pathogenesis, diagnosis and prognosis of acute leukemia (AL). We studied five AL-related miRNAs to confirm the significance of these miRNAs in AL. Samples tested included acute myeloid leukemia (AML), 107 cases; acute lymphoblastic leukemia (ALL), 40 cases. Five AL-related miRNAs: miR-128, let-7b, miR-223, miR-181a and miR-155 expression were detected by qRT-PCR. Analysis showed that miRNA-128 expression was significantly higher in ALL (P<0.001). However, the let-7b and miR-223 expressions in ALL were significantly lower than in AML (P<0.001). Compared with normal controls, miR-128 expression was significantly higher in ALL (P<0.001), but there was no significant difference in AML (P=0.900). The expressions of Let-7b and miR-223 in AL group were higher than in normal controls (P<0.001). MiR-181a was quantitatively detected in 107 AML patients, and we found that the expression of miR181a in M1 or M2 patients was significantly higher compared with it in M4 or M5 (P=0.013). According to karyotype, 84 cases of AML were classified into three groups named favorable, moderate and poor. It was found that the expression of miR-181a in favorable prognosis group was significantly lower than in poor prognosis group (P=0.015). In FLT3-ITD mutation positive patients, the miR-155 expression was significantly higher than in the negative group (P=0.002). These results support that miR-128, let-7b, miR-223 and miR181a have a diagnosis value in AL, while miR-181a and miR-155 are of great prognostic significance in AML.