Objective To explore the effect of early warning system in pediatric critical illness or potential critical illness. Methods The early warning system of pediatrics was established and applied to pediatric hospitalized children.A total of 568 children admitted to the hospital from August to December 2015 were selected as the research objects, and were divided into the observation group (295 cases) and the control group (273 cases) using the random number table method.The control group was treated with routine evaluation and treatment, and the observation group was treated with early warning management.The rates of unplanned admission PICU, average hospitalization days and doctors' satisfaction to nurses were compared between the two groups. Results In the observation group, the unplanned admission rate of PICU and the average length of stay were 1.69% and(4.06±1.42) days respectively, which were lower than 5.13% and (5.21±3.21) days in the control group, and the differences were statistically significant (P<0.05). Doctors' satisfaction with nurses' active observation and accurate reporting of their conditions was significantly higher than that of the control group, with statistically significant differences (P<0.05). Conclusion The establishment and application of pediatric early warning system can effectively improve the early recognition ability of medical staff for children with critical illness, timely intervention and treatment, and improve the prognosis of children. Key words: Pediatrics; Early warning system; Construction; Critical illness