Objective To analyze the value of procalcitonin (PCT), C-reactive protein (CRP), and blood routine indicators in the diagnosis of children with respiratory tract infections. Methods A total of 85 hospitalized children treated at Yulin Hospital, The First Affiliated Hospital of Xi'an Jiaotong University from May 2021 to September 2023 were selected for the retrospective study, including 52 boys and 33 girls. They were 3-12 years old. Their body weight was 20-33 kg. They were divided into a respiratory tract infection group (35 cases) and a non-respiratory tract infection group (50 cases) according to whether they had infections. The binary logistic regression model was used to analyze the factors influencing respiratory tract infections in the children. The receiver operating characteristic curve (ROC) was drawn to evaluate the diagnostic value of the children with respiratory tract infections. According to the types of pathogens, the children were divided into a bacterial infection group (11 cases), a mycoplasma infection (11 cases), and a viral infection group (13 cases), and the levels of PCT, CRP, and blood routine indicators were compared between the 3 groups. t, χ2, and F tests were used as the statistical methods. Results The PCT, CRP, platelet count (PLT), white blood cell count (WBC), and percentage of neutrophils (NEUT) in the respiratory tract infection group were higher than those in the non-respiratory tract infection group, with statistical differences (t=4.537, 4.472, 4.570, 4.297, and 4.453 ; all P<0.05). The results of the logistic regression model analysis showed that PCT (OR=16.750, 95%CI 3.777-74.283), CRP (OR=1.478, 95%CI 1.193-1.831), PLT (OR=10.071, 95%CI 2.911-34.843), WBC (OR=1.669, 95%CI 1.257-2.216), and NEUT (OR=1.187, 95%CI 1.083-1.301) were influential factors in the diagnosis of respiratory tract infections in the children (all P<0.05). According to ROC analysis, the sensitivities of PCT, CRP, PLT, WBC, and NEUT in the diagnosis of respiratory tract infections in the children were 0.686, 0.743, 0.714, 0.829, and 0.543, respectively; the specificities were 0.620, 0.600, 0.800, 0.780, and 0.820, respectively. The area under the curve of the combination of PCT, CRP, PLT, WBC, and NEUT in the diagnosis of respiratory tract infections in the children was 0.897. Conclusion PCT and CRP combined with blood routine are of high value in the diagnosis of respiratory tract infections in children, and can provide reliable basis for clinicians to diagnose the pathogen types.