Purpose This study aims to investigate the diagnostic value of baseline F18 fluorodeoxyglucose (FDG) PET/computed tomography (CT) parameters and peripheral blood inflammatory markers in aggressive lymphoma of non-Hodgkin lymphoma (NHL) and the correlation between peripheral blood inflammatory markers and maximum standardized uptake value (SUV max ). Patients and methods We conducted a retrospective analysis including 121 patients with NHL. Patients were divided into aggressive lymphoma group and indolent lymphoma group. Mann–Whitney U test, chi-square test and multivariate stepwise logistic regression were used to analyse. Subsequently, receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic performance. Additionally, Spearman correlation analysis was utilized to explore the correlation between peripheral blood inflammatory markers and SUV max . Results Leptin mass criterion uptake value (SUL) max , SUV max , SUV avg , SUV peak , focal SUV max /liver SUV max , focal SUV max / mediastinal SUV max , SUL avg , SUL peak , systemic immune-inflammation, neutrophil ratio, total lesion glycolysis, neutrophils versus lymphocyte ratio, platelet-to-lymphocyte ratio, hemoglobin-to-white blood cell ratio, lactate dehydrogenase and lymphocyte ratio between two groups were statistically significant ( P < 0.05). SUV max was an independent influencing factor, and the area under the ROC curve was 0.862. There was a positive correlation between the platelet-to-lymphocyte ratio and SUV max ( r = 0.239; P = 0.008). Conclusion PET/CT parameters and peripheral blood inflammatory markers have certain value in the diagnosis of aggressive lymphoma in NHL, among which SUV max is an independent influencing marker and is positively correlated with PLR.