Objective To investigate the trend of under-5 death and factors associated with it in Yanchi, Wuzhong, Ningxia Hui Autonomous region from 2011 to 2020, so as to provide evidence for formulating intervention measures.

Methods Under-5 death children in Yanchi County 2011 - 2020 were recruited as study subjects retrospectively from the National Maternal and Child Health Monitoring Information System. Statistical analysis was conducted on Under-5 mortality rate and causes of death.

Results The neonatal mortality rate, infant mortality rate and under 5 mortality rate showed a downward trend from 2011 to 2020, dropping from 7.80 ‰, 11.50 ‰, and 13.60 ‰ to 0.00 ‰, 0.62 ‰, and 2.47 ‰, respectively, and the trends were statistically different between various years (χ_trend²=12.228, 18.269, 21.170, all P < 0.001). Premature delivery or low birth weight, pneumonia, birth asphyxia, accidental death, congenital heart disease and other congenital abnormalities were the main causes of death of children under 5 in Yanchi County from 2011 to 2020.

Conclusion Under 5 mortality rate in Yanchi County shows a downward trend 2011 - 2020. Further strengthening health management, promoting health education, and improving health professionals' technical competence can effectively reduce under 5 mortality rate.