Objective To evaluate the clinical efficacy and toxicity of rituximab combined with CHOP (R-CHOP) in the treatment of relapsed or refractory diffuse large B cell lymphoma (DLBCL).Methods 30 patients were enrolled.All patients,pathologically confirmed to be CD20 positive DLBCL (all in stages Ⅲ-Ⅳ ), were relapsed or refractory after received 2-6 cycles of chemotherapy. Then all of them received R-CHOP schedule for 4 to 6 cycles, each cycle was 21 days. Clinical data before and after R-CHOP were collected.A retrospective analysis of the R-CHOP therapy,either compared to the literature or self-control was performed to evaluate the efficacy and toxicity. Results All the 30 patients were evaluable, induding 15 cases were complete remission (CR), 10 cases were partial remission (PR), 3 cases were stable disease (SD),and 2 cases were progressed disease (PD).The CR rate was 50.0 ％ (15/30),the total response rate (RR) was 83.3 ％ (25/30).All patients were well tolerated to the therapy.Only 3 cases were Ⅱ degree neutropenia,1 case was Ⅰ degree thrombocytopenia, and 2 cases suffered nausea and other mild gastrointestinal discomfort. Conclusions R-CHOP regimen could also achieve good response for relapsed or refractory DLBCL significantly.The common adverse effects of rituximab were mild.All the patients were well tolerated.