The expression of CD73 by flow cytometry (FC) in bone marrow (BM) specimens of B-cell acute lymphoblastic leukemia (B-ALL) with or without minimal residual disease (MRD) was studied, and its advantages were evaluated using the MRD assay. This study also detected the expression profile of CD73 in hematogones and mature B cells in BM specimens of 18 healthy donors. Results showed that the mean value of CD73 expression in MRD-positive B cells was 6-fold greater than that in the MRD negative ones. Also, 41.82% MRD-positive B-ALL cases expressed high CD73 and the sensitivity of CD73-based MRD detection reached 10(-4). Since the expression of CD73 increases with the maturation of normal B cells, it is better to mix it with CD34, CD10 and CD20 in one tube to prevent the disturbance of mature B cells. CD73 is recommended as an optional MRD marker for B-ALL patients by using FC.