The R-CHOP combined chemotherapy has largely improved the curability of patients with CD 20+ diffuse large B cell lymphoma (DLBCL). As classic methods for predicting the prognosis, now 18F-FDG PET and international prognostic index (IPI) is facing the challenge of rituximab. This paper summarizes the predictive efficiency and research advances of two methods. For PET, the assessment has been changes from traditional vision assessment to quantitative/semi-quantitative parameter assessment. For IPI, ages and LDH levels are refined and grouped. After comparison, it is recommended that two methods should be integrated in order to better predict the development of the disease.