Objective To explore the clinical significance of minimal residual disease (MRD) and WT1 in patients with acute myeloid leukemia (AML).Methods 349 bone marrow specimens of 42 patients with AML (except M3) before and after chemotherapy were collected.The expression level of MRD was determined by flow cytometry (FCM) and WT1 gene was detected by real time quantitative PCR (RQ-PCR).Results No correlation was observed between WT1 gene expression level of AML patients before chemotherapy with treatment response (x2 =0.166 3,P ＞ 0.5).34 AML patients achieved morphological complete remission (CR) after the first course of inductive chemotherapy.The recurrence rate was significantly higher in patients with high MRD level than that in those with low MRD level (63.6 ％ vs 21.7 ％) (x2 =5.729,P ＜ 0.025),and significantly higher in patients with high WT1 expression than that in those with low WT1 expression (87.5 ％ vs 23.1％) (x2 =10.749,P ＜ 0.005).WT1 expression level of patients with CR was significantly lower than that of patients without CR (t =4.669,P ＜ 0.001).The recurrence rate of patients with both low level of MRD and WT1 was significantly lower than those of either high level of MRD and WT1 (15.0 ％ vs 64.3 ％,P ＜ 0.05).The level of WT1 in patients with CR had positive correlation with the level of MRD (r =0.835,P ＜ 0.001).Conclusions MRD and WT1 have great importance in evaluating the therapeutic effects among patients with AML and increasing the positive rate of MRD.They also provide experimental basis for the individual and gradation treatment in the clinic.