Objective:To study the value of response assessment of interim fluorie-18fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT) in patients with diffuse large B-cell lymphoma (DLBCL). Methods: A total of 32 DLBCL patients confirmed by pathology underwent 18F-FDG PET/CT before and after chemotherapy. According to the revised response criteria for malignant lymphoma 2007, the patients were divided into two groups. Independent samples t-test and binary logistic analysis were performed. Results: The differences of SUV4max (mid chemotherapy, after 4 chemotherapy cycles) and Δ SUVmax (the difference between SUV0max and SUV4max) between the CR+PR group and the SD+PD group were significant (P=0.021, P=0.028). Comparing the SUV0max (SUVmax before chemotherapy) of the CR+PR group and the SD+PD group, respectively, there were no statistical significances (P=0.494). Binary logistic analysis showed that SUV4max had a significant impact on the clinical effect (OR=0.646). Conclusion: The interim 18F-FDG PET/CT may be useful for the evaluation of chemotherapy and the guidance of subsequent treatment in DLBCL.