Abstract： Objective To investigate the prognostic value of △SUV and Deauville 5-point scoring (5-PS) in patients with DLBCL.Methods Thirty-nine patients (20 males,19 females;median 58 (23-85) years) with pathologically confirmed DLBCL were retrospectively analyzed from January 2009 to April 2015.PET/CT imaging was performed before and after 4 courses of chemotherapy.The optimum cutoff values of △SUVmax and its decline proportion (△SUVmax％) were calculated by ROC curve,and then the Kaplan-Meier analysis and Cox regression analysis were performed in patients with different △SUVmax and △SUVmax％.Patients were also evaluated by the observers using Deauville 5-PS,Kaplan-Meier analysis and Cox regression analysis were performed in patients with scores ≥ 4 and those with scores ＜ 4.x2 test and Spearman correlation analysis were used.Results (1) There were 10 patients (25.64％,10/39) with progressed disease within the 2 year-follow-up.The △SUVmax,△SUVmax％ of progressed group were markedly lower than those of non-progressed group:9.55± 11.90 vs 15.61±7.86,71.66％ (33.90％-78.91％) vs 87.83％(76.51％-92.43％);t=-2.37,z=-3.25,both P＜0.05.(2)The optimum cutoff values of the △SUVmax,△SUVmax％ were 11.2 and 72.88％ respectively.(3) The patients with △SUVmax ＜ 11.2,△SUVmax％ ＜72.88％ or Deauville 5-PS≥4 showed shorter PFS and △SUVmax％ was proved to be an independent prognostic factor(x2 =5.734,14.821,5.851,all P＜0.05).(4) △SUVmax％ and Deauville 5-PS were correlated (rs =-0.633,P＜0.001).Conclusions △SUV and Deauville 5-PS could be used for prognosis prediction in DLBCL patients and △SUVmax％ might be an independent predictive factor.The values of △SUVmax ％ and Deauville present a negative relationship.