Objective To explore the risk factors associated with delayed discharge in children with adenovirus pneumonia and construct a model to provide reference for reducing hospitalization time and developing intervention plans for delayed discharge in children with adenovirus pneumonia. Methods A retrospective analysis was conducted on the clinical data of 237 children with adenovirus pneumonia admitted to the Children's Hospital of Nanjing Medical University from August 2022 to February 2024. The patients were divided into a delayed discharge group and a non-delayed discharge group based on their hospitalization time (with 10 days as the cut-off point, i.e., <10 days or ≥10 days). Univariate analysis and multivariate Logistic regression analysis were used to screen the influencing factors of delayed discharge in children with adenovirus pneumonia. Results A total of 41 patients had delayed discharge, the incidence of delayed discharge was 17.30% (41/237). There were significant differences in age, fever duration during hospitalization, severity of disease, C-reactive protein and procalcitonin between the delayed discharge group and the non-delayed discharge group (P<0.05). Multivariate Logistic regression analysis showed that age (OR=3.305, 95%CI: 1.450-7.534), duration of fever during hospitalization (OR=3.822, 95%CI:1.492-9.790), severity of disease (OR=3.574, 95%CI: 1.458-8.760), C-reactive protein (OR=1.061, 95%CI: 1.005-1.119), procalcitonin (OR=24.796, 95%CI: 6.155~99.891) were independent risk factors for delayed discharge in children with adenovirus pneumonia, and the difference was statistically significant (P<0.05). Probabilistic prediction model P=1/［1+e-(-14.041+1.196*X1+1.341*X2+1.274*X3+0.059*X4+3.211*X5)］, the overall accuracy of the model prediction is 88.3%. The result of Omnibus test showed P<0.001. The accuracy of prediction was 74.1% after the cross-validation of 5 fold. Conclusion Age, non-standard medication use before admission, fever duration during hospitalization, disease severity, CRP, and PCT are all influencing factors for delayed discharge in children with adenovirus pneumonia. Healthcare professionals can focus on high-risk individuals for delayed discharge based on these factors and formulate corresponding preventive measures, which may help improve clinical treatment outcomes and shorten hospitalization time