Abstract: Objective To analyze the expression levels of serum amyloid A(SAA) and high-sensitivity C-reactive protein(hs-CRP) in children with respiratory tract infection and their application value in early diagnosis. Methods Total 70 children with respiratory tract infection diagnosed and treated in our hospital from March 2019 to March 2020 were selected and included in the study group. According to the results of etiological examination, they were divided into group A(bacterial infection group) and group B(viral infection group), and 35 healthy children who received routine physical examination in our hospital at the same time were selected and included in the control group. The venous blood of upper limbs was collected on an empty stomach in the study group at the beginning of admission(acute stage) and recovery period, while the control group was collected once. SAA and hs-CRP were detected. The application value of SAA and hs-CRP in early diagnosis of respiratory tract infection in children was analyzed. Results The levels of SAA and hs-CRP in the group A and B at the beginning of admission were higher than those in the control group(all P<0.05). The levels of SAA and hs-CRP in the group A at the beginning of admission and in the recovery period were higher than those in the group B(all P<0.05). The levels of SAA and hs-CRP in the recovery period in the group A and B were lower than those in the beginning of admission(all P<0.05). The sensitivity, specificity, positive predictive value, negative predictive value of SAA combined with hs-CRP(97.14%, 97.14%, 97.14%, 94.28%) were higher than those of SAA alone(87.14%, 80.00%, 89.71%, 75.68%) and hs-CRP alone(45.71%, 68.57%, 74.42%, 38.71%), all P<0.05. Conclusion SAA combined with hs-CRP detection has high application value in the early diagnosis of respiratory tract infection in children, which can provide important reference for clinical diagnosis and is worth carrying out.