Objective To analyze the cause of death of children under 5 years old in Yandu District,Yancheng City,so as to provide a basis for formulating response strategies and measures for children's health care. Methods The death data of children under 5 years old were obtained from the chronic disease management information platform of Jiangsu Province.The annual mortality rate and the composition of major causes of death were calculated. Results During the period of 2017 to 2022,the mortality rate of children under 5 years old in Yandu District was 8.41‰,9.13‰,6.00‰,7.08‰,3.68‰ and 5.25‰,respectively,with an average of 6.81‰.The mortality showed a downward trend (χ²_trend =6.265,P=0.012).Among the 123 children who died under 5 years old,72 (58.54%) were male and 51 (41.46%) were female.No differences were found between male and female (χ²=2.753,P=0.097).The top three main causes of death in children aged 0 to ＜1 years (infants) were birth asphyxia (17.89%),preterm low birth weight (8.13%),and congenital heart disease (6.50%).The top two causes of death in children aged 1 to ＜5 years were drowning (11.38%) and falling from high altitude (7.32%),respectively.The main place of death for children was medical institutions (41.46%),and those medical institutions were mainly at the provincial (municipal) level (81.30%). Conclusion The mortality rate of children under 5 years old in Yandu District, Yancheng City is showing a downward trend, and effective intervention measures need to be taken to ensure the health and quality of life of children.