In china, previous studies showed patients with non-Hodgkin lymphoma (NHL) are likely to have hepatitis B virus (HBV) infection. The risk of HBV reactivation is high when patients were treated with CHOP, especially in combination with rituximab. The aim of this study is to compare entecavir with lamivudine, 2 commonly used anti-virus agents, for preventing the risk of HBV reactivation in patients with NHL on CHOP/R-CHOP.