• Previously untreated CD20 Positive DLBCL.

• International Prognostic Index (IPI) score of 0 to 2, Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2.

• 18 years to 70 years; Male or female patients; Body Mass Index (BMI)≤2.13 m\^2.

• Expected survival more than 6 months.

• At least 1 bi-dimensionally measurable lesion: Nodal lesion: Greatest transverse diameter≥1.5cm and short axis≥1.0cm; Extra-nodal lesion: Greatest transverse diameter≥1.0cm.

• Cardiac echocardiography: LVEF≥50%.

• Adequate hematological function: WBC≥3 x 10\^9/L, HGB≥80g/L, ANC≥1.5 x 10\^9/L, PLT≥75 x 10\^9/L.

• Hepatic function: TBIL≤1.5 x ULN, ALT or AST≤2.5 x ULN, ALP≤3 x ULN if with no bone marrow infiltration, Renal function: Cr≤1.5 x ULN.

• Seronegative for HCV antibody, or HIV antibody, or hepatitis B virus surface antigen (HBsAg). HBc antibody seropositive, but HBV DNA and HBsAg negative patients may participle following consultation with a hepatitis expert regarding monitoring and use of HBV antiviral therapy, and provided they agree to receive treatment as indicated.

⁃ Must agree to take effective birth control methods or are not of childbearing potential. Women must agree to continue contraceptive measures within 12 months after the last treatment. Men must agree to continue contraception within 3 months after the treatment.

⁃ All patients must have signed an informed consent document.