Abstract: It is believed that malignant tumor patients with hepatitis B virus (HBV) infection show a higher incidence of reactivation of HBV after receiving chemotherapy, which is fatal,suggesting that awareness of HBV reactivation and the principles of prevention and treatment is important.There are many studies on HBV reactivation, however, the data are scattered.Here, we summarize the current understanding of the prevention and treatment of HBV reactivation in malignant tumor patients with HBV after receiving chemotherapy, aiming at providing routine screening and treatment for these patients which protect them against reactivation of HBV and improve the quality of life of patients.