• DLBCL was confirmed by histology according to world Health Organization (WHO) disease classification (excluding primary central lymphoma and HIV-associated lymphoma);

• There are evaluable lesions detected by PET/CT;

• Life expectancy of more than 3 months;

• Prior treatment with sufficient first-line anti-lymphoma therapy, no remission within 90 days of the last administration, or disease progression after sufficient first-line anti-lymphoma therapy, and no current anti-lymphoma therapy (≥2 weeks since the last anti-lymphoma therapy). Patients were allowed to receive hormone drugs or rituximab at least 1 week after enrollment for symptom control reasons;

• 18≤ age ≤75 years old, male and female;

• ECOG 0-2 points;

• No serious organic lesions in the main organs, meeting the requirements of the following laboratory examination indicators (conducted within 7 days before treatment) :

• ① Absolute value of neutrophil count ≥1500/mm3; Platelet count ≥75,000/mm3

• ② Total bilirubin ≤2× upper limit of normal value (ULN)

• ③ Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (serum glutamate pyruvate aminotransferase \[SGPT\]) ≤3× upper limit of normal value (ULN)

• ④ the creatinine clearance rate was ≥60ml/min

• ⑤ No cardiac dysfunction

• If the subject is of reproductive age and requires effective contraception, he/she agrees to comply with all contraceptive requirements: 1) there are fertile women have to decide, at the same time take two reliable contraceptive methods (a kind of high efficient contraceptives - tubal ligation, intrauterine contraceptive device, hormone (birth control pills, needle, patch, vaginal ring or implants) or partner vasectomy, another effective birth control method -- men or synthetic rubber condom, diaphragm or cervical cap). 2) Unless hysterectomy, effective contraception is required even if there is a history of infertility;

• Fertile men must always use rubber or synthetic condoms when having sexual contact with fertile women during the use of this product and within 28 days of discontinuation of this product, even if they have successfully vasectomy; The subjects knew the characteristics of the disease, voluntarily joined the study, received treatment and follow-up, and the informed consent was signed by the subjects themselves or their guardians and impartial witnesses.