Objective: To investigate the predictive value of peripheral blood B-cell activating factor (BAFF) on the severity of allergic rhinitis (AR) disease. Methods: Eighty patients with AR admitted to our hospital from January 2019 to October 2019 were selected as the AR group, and the patients were divided into mild and moderate-severity groups according to symptom scores; 50 healthy physical examiners in the same period were selected as the health control group. The expression levels of serum BAFF in different groups were analyzed and compared. The predictive value of serum BAFF on the severity of AR patients was analyzed by receiver operating characteristic curve. Results: Serum BAFF concentrations were significantly higher in the AR group than in the control group (P <0.05). Compared with patients in the mild AR group, serum BAFF concentrations were significantly higher in the moderate-severe group, and the difference was statistically significant (P<0.05). Serum BAFF levels were positively correlated with peripheral blood eosinophil number and ratio, total IgE level,visual analogue scale (VAS) score and total nasal symptoms score (TNSS) score in AR patients. Receiver operating characteristic curve results showed that compared with total IgE levels, serum BAFF had better ability to differentiate disease in AR patients, with a sensitivity of 0.550 and specificity of 0.825. Conclusion: Increased peripheral blood BAFF concentrations in AR patients correlate with the degree and severity of eosinophilic inflammation of the disease and can be used as a marker to predict the severity of the disease.