Objective To determine the risk factors associated with peripheral intravenous therapy infiltration and extravasation (PIVIE) in paediatric surgery inpatients. Methods This retrospective observational study was conducted at a tertiary general hospital in Sichuan, China. Logistic regression was employed to identify independent risk factors predictive of PIVIE. Kaplan–Meier survival analysis was undertaken to determine the relationship between the occurrence of PIVIE and the duration of that event (survival time). Results This study included 11 006 paediatric surgery inpatients and 19 771 peripheral intravenous catheters (PIVCs). The incidence of PIVIE was 16.93% (3347 of 19 771). The following were significant predictors of PIVIE: sex (odds ratio [OR] 0.834; 95% confidence interval [CI] 0.772, 0.900); age (OR 0.945; 95% CI, 0.934, 0.956); disease classification (OR 0.962, 95% CI 0.950, 0.976); puncture site (OR 1.061; 95% CI 1.044, 1.078); and indwelling time (OR 1.257; 95% CI 1.215, 1.300). Conclusions Sex, age, type of disease, puncture site and indwelling time were risk factors for PIVIE. The puncture site should be effectively assessed and accurately selected. Informed judgements should be based on the child’s sex, age and medical condition, so that the appropriate preventive measures to minimize the risk of PIVIE can be implemented.