Abstract: OBJECTIVE To explore the peripheral blood interleukin-6 (IL-6), tumor necrosis factor-α(TNF-α), interferon-α(IFN-α), eosinophils(EOS)of the bronchial asthma children complicated with influenza A virus infection and observe their association with severity of disease. METHODS A total of 135 bronchial asthma children who were complicated with influenza A virus infection and treated in Jinan Maternity and Child care Hospital Affiliated to Shandong First Medical University from Dec. 2023 to Oct. 2025 were assigned as the infection group, and the patients of the infection group were divided into the mild group with 45 cases, the moderate group with 50 cases and the severe group with 40 cases according to the severity of illness condition. Meanwhile, 40 children with simple bronchial asthma were chosen as the non-infection group, and 40 healthy children who received physical examination were chosen as the healthy control group. The levels of peripheral blood IL-6, TNF-α, IFN-α and EOS were detected and compared among the groups. RESULTS The peripheral blood IL-6, TNF-α and EOS of the severe group were respectively (85.64±10.27)pg/ml, (65.41±8.52)pg/ml and (0.65±0.12)×10⁹/L, higher than those of the mild group, the moderate group, the non-infection group and the healthy control group (P＜0.05); the IFN-α level of the severe group was (12.35±2.84)pg/ml, lower than that of the mild group, the moderate group, the non-infection group and the healthy control group(P＜0.05). The IL-6, TNF-α and EOS were positively correlated with the severity of disease(r_s=0.724, 0.691, 0.578,all P＜0.001); the IFN-α was negatively correlated with the severity of disease (r_s=-0.613,P＜0.001). CONCLUSIONS The peripheral blood IL-6, TNF-α, EOS and IFN-α of the bronchial asthma children complicated with influenza A virus infection are closely associated with the severity of diseases. The joint detection of the above indexes may facilitate the assessment of illness condition of the children.