Objective：This study aims to investigate the value of interleukin 24（IL-24）in predicting the treatment outcomes of diffuse large B cell lymphoma（DLBCL）. Methods：The 82 patients with DLBCL who were enrolled in our hospital were received 4 courses of rituximab combined with cyclophosphamide+hydroxyldaunorubicin + oncovin + prednisone（CHOP）routine first-line treatment. The patients were divided into the treatment-effective group（complete remission and partial remission）and the treatment-ineffective group（stable disease and progressive disease）according to the treatment outcomes，and 66 healthy subjects were selected as the control group at the same time. The IL-24 level in peripheral blood of the tested population was analyzed by ELISA and the predictive value of IL-24 in the clinical treatment of DLBCL was evaluated by ROC curve. Results：Before treatment，the IL-24 levels in patients with DLBCL［（41.4±7.3）μg/mL］were significantly lower than those in healthy subjects［（61.4±9.3）μg/mL，P < 0.001］. In the treatment-effective group，the IL-24 level increased after treatment［（55.0±7.0）μg/mL vs.（46.3±5.3）μg/mL，P < 0.001］，and was significantly higher than that in treatment-ineffective group［（55.0±7.0）μg/mL vs.（36.5±4.2）μg/mL，P < 0.001］. However，the IL-24 level in the treatment-ineffective group had no statistical difference after treatment（P > 0.05）. When 38.8 μg/mL was taken as the IL-24 optimal threshold，the sensitivity and specificity of IL-24 to predict the effectivity of DLBCL treatment were 95.65% and 83.33%，respectively. Conclusion：IL-24 has a reliable predictive value in the clinical treatment of patients with DLBCL.