Abstract: Objective: To analyze the clinical characteristics of primary tonsillar diffuse large B-cell lymphoma(PTDLBCL), and built a prediction model to predict individual′s prognosis.Methods: The characteristic information, treatment record and survival information of 711 patients with PTDLBCL diagnosed from 2004 to 2015 were obtained from the Surveillance, Epidemiology, and End Results(SEER) Database of American National Cancer Institute. Prognostic factors were screened by COX model stepwise regression analysis in 711 cases. COX regression equation was fitted by rms R software package and a nomogram model was established. Bootstrap method was used to verify the model internally. The discriminant degree was verified by calculating Harrell's C index, and its accuracy was evaluated by drawing calibration curve and calculating Brier score.Results: The stepwise regression analysis results showed that the elderly(≥66 years), Ann Arbor stage Ⅲ or Ⅳ, with B symptoms and did not receive radiation and chemotherapy for PTDLBCL patients were adverse factors. Five prognostic factors were incorporated into the regression equation constructed by cph R software function. Based on this, the nomograph was drawn, and the Harrell's C index and Brier score were calculated as 0.759 and 0.121 respectively. Bootstrap method was used for internal verification, and the Harrell's C index and Brier score were 0.753 and 0.124 respectively. The calibration curves of 3-year and 5-year overall survival were all close to the ideal curve, indicating that the accuracy and differentiation of this model were good.Conclusion: The prognostic prediction model of PTDLBCL we built has good predictive value, which can assist clinical individualized analysis for survival and prognosis of PTDLBCL patients.