Objective To investigate the levels of serum pentametin 3(PTX3)and cytokine signal trans-duction inhibitor 3(SOCS3)in children with recurrent upper respiratory tract infections(rURTIs)and their diagnostic value.Methods A total of 132 children with rURTIs who were treated in the Huanghua People's Hospital from August 2020 to August 2023 were selected as the study group,and were divided into mild group(75 cases),moderate group(43 cases)and severe group(14 cases)according to clinical pulmonary infection score.A total of 130 healthy children who underwent physical examination in Huanghua People's Hospital were selected as the control group.Serum levels of PTX3,SOCS3,interleukin(IL)-6,tumor necrosis factor-α(TNF-α)and C-reactive protein(CRP)were determined by enzyme-linked immunosorbent assay.The serum PTX3 and SOCS3 levels and their correlation with IL-6,TNF-α and CRP levels in rURTIs children were anal-ysised by Pearson correlation.The factors affecting the occurrence of rURTIs were analyzed by multivariate Logistic regression,and the clinical value of serum PTX3 and SOCS3 levels in the diagnosis of rURTIs were analyzed by receiver operating characteristic(ROC)curve.Results Compared with the control group,the ser-um levels of PTX3,SOCS3,IL-6,TNF-α and CRP in the study group were increased(P＜0.05).The serum PTX3 and SOCS3 levels increased with the severity of rURTIs disease(P＜0.05).The serum PTX3 level in rURTIs children was positively correlated with SOCS3(r=0.642,P＜0.05),and the serum PTX3 and SOCS3 levels in rURTIs children were positively correlated with IL-6,TNF-α and CRP(P＜0.05).Serum PTX3,SOCS3,IL-6,TNF-α and CRP were the risk factors of rURTIs(P＜0.05).The area under the curve of the serum PTX3 and SOCS3 levels and the combined diagnosis of rURTIs were 0.833,0.833 and 0.914,re-spectively,which were significantly higher than those of the combined diagnosis(Zcombined-PTX3=2.607,Zcombined-SOCS3=2.679,P＜0.05).Conclusion Serum levels of PTX3 and SOCS3 were significantly increased in children with rURTIs,and they were positively correlated.The combination of PTX3 and SOCS3 could be used for early diagnosis of rURTIs.