Abstract: Minimal residual disease (MRD) has been used not only for relapse prediction, prognosis re-classification and directing pre-emptive therapy of patients with acute leukemia, but also in the field of therapy for patients with other hematological malignancies or solid tumors. A deep understanding of the intension and extension of MRD is important for exploring novel methods for accurate prediction of relapse and consummating the individualized intervention strategies for malignant tumors.