Risk staging is the cornerstone of individualized leukemia treatment, and is based on accurate MICM staging and the clinical presentation of the child. Currently, the following risk factors are recognized: ① leukocyte level at diagnosis (excluding hormone application and blood transfusion, the highest level of leukocytes before treatment) ≥ 50×109/L (NCI criteria); ② age <1 year or ≥10 years at diagnosis (NCI criteria); ③ t(12;21)/TEL-AML1 positive indicates good prognosis, and many treatment groups classify it as standard risk without considering the child's (4) t(9;22)/BCR-ABL, t(4;11)/MLL-AF4 positive; (5) T-lymphocytic leukemia (T-ALL), especially in children with high leukocyte levels, age >10 years, and mediastinal masses; (6) peripheral blood naïve cells on day 8 of treatment [oral prednisone on days 1-7 and methotrexate (MTX) monotherapy sheath injection on day 1]. count >1000/μl; (7) bone marrow remission status of M3 at day 15 of treatment; (8) bone marrow not reaching complete remission at day 33 of treatment; (9) high level of microscopic residual disease (MRD) at day 33 and/or week 12 of induction remission treatment. ALL is usually classified into standard-risk, intermediate-risk, and high-risk types based on the above risk factors at home and abroad. The US COG Collaborative Group subdivided each type into two groups according to MRD levels and gave different intensities of chemotherapy.