This study aims to understand the clinical characteristics of severe fever with thrombocytopenia syndrome (SFTS) and screen risk factors for the prognosis. This retrospective study collected the epidemiological, demographic, and clinical and laboratory data of 101 patients with SFTS. Patients were divided into survival and deceased groups, and then logistic regression model was used to evaluate the association between predictors and prognostic variables. A joint detection factor model was constructed, and a receiver operating characteristic (ROC) curve was drawn. A nomogram was established using the R language, and its efficiency in the diagnosis of SFTS was evaluated using the Calibrate curve. Patients in the deceased group were more likely to show an elder age, a shorter hospitalization stay, renal failure and multiple organ failure compared with that of the survival group. There were statistical differences in the neutrophil percentage, lymphocyte percentage, neutrophil-to-lymphocyte ratio, platelet (PLT), AST, AST/ALT, blood urea nitrogen, lactate dehydrogenase, hydroxybutyrate dehydrogenase, thromboplastin time and activated partial thromboplastin time between the two groups. Lymphocyte percentage, PLT, and AST/ALT were independent risk factors for mortality in SFTS patients. We established a prediction model for SFTS mortality with good efficiency.