Leukaemia is a major disease that seriously endangers human health, the long-term survival rate of acute myeloid leukaemia receiving conventional chemotherapy is only 10% to 45%, haematological relapse is the main cause of treatment failure in acute myeloid leukaemia, reducing the relapse rate is the key to improving the efficacy of acute leukaemia, biomarker-guided preemptive therapy is an effective way to reduce the recurrence of leukaemia, existing markers to predict the recurrence has a high false Existing markers have high false-negative and false-positive rates for predicting relapse, and improving the accuracy of leukaemia relapse prediction is a major clinical problem that needs to be solved urgently. The group has found that circulating leukaemia stem cells remaining after chemotherapy are the key to relapse, therefore, we propose to conduct a multicentre prospective clinical study on the prediction of acute leukaemia relapse by circulating leukaemia stem cells.