Chemotherapy for leukemia is about 7 days or 28 days at a time, the exact time should be decided according to the type of leukemia as well as the chemotherapy regimen. 1. There are 8 types of acute myeloid leukemia, of which the non-M3 type is usually treated with DA regimen, i.e., erythromycin plus cytarabine, or HA regimen, i.e., hypertriglyceride and cytarabine, and the duration of chemotherapy is 7 days. 2. Acute myeloid leukemia type M3 is acute promyelocytic leukemia, the chemotherapy program of this type is usually using retinoic acid and arsenite, and at the same time, the combined use of cytarabine or Zorubicin, the duration of a course of treatment is usually about 7 days, but different patients with different chemotherapy programs, the specific time needs to be based on the patient’s chemotherapy program and the recovery situation to decide. 3. Acute lymphoblastic leukemia, usually the standard length of a chemotherapy session is about 28 days, the drugs include cyclophosphamide, vincristine and so on. The specific duration of chemotherapy for leukemia is recommended to consult the doctor of the local hospital, and choose the correct chemotherapy plan and formulate a standardized chemotherapy course under the doctor’s guidance.