Objective To explore the prevalence and predictors of ineffective airway clearance （IAC） in children with pneumonia in PICU, and to provide reference for nurses to prevent and identify IAC. Methods Cluster sampling method was used and a total of 302 pneumonia children admitted to PICU in 3 3A hospitals were selected.General information, clinical disease information, clinical indications and occurrence of IAC were collected. Results Totally, 227 children （75.17%） developed IAC.Binary logistic regression analysis showed that ineffective cough, phlegm sound and viscous sputum were predictors of IAC （P＜0.05 for all）. Conclusion The incidence of IAC is high in children with pneumonia in PICU, and the children with ineffective cough, phlegm sound and viscous sputum are more prone to develop IAC.Clinical medical staff need to ramp up assessment of children′s ability tocough, of breathing sounds and sputum, so as to identify IAC early on and take appropriate measures.