Objective: To analyze the trend of child and adolescent mortality rate in China from 2004 to 2018 and explore the possible policy effects. Methods: This study used the mortality data of child and adolescent aged 5 to 19 years from 2004 to 2018 based on the National Disease Surveillance System. Age-standardized mortality rate was calculated by using the population from the sixth national census. Joinpoint regression was used to analyze the trend of child and adolescent mortality with different features from 2004 to 2018. Results: From 2004 to 2018, the overall mortality rate of children and adolescents in China dropped from 40.02 per 100 000 to 22.00 per 100 000, and the average annual percentage change (AAPC) was -4.28 (95%CI:-5.35,-3.20,P<0.001). The mortality rate dropped rapidly from 2004 to 2006, and the annual percentage change (APC) was -9.20 (95%CI:-15.63,-2.28,P=0.017). The decline rate slowed down between 2006 and 2013, and the APC was -1.56 (95%CI:-2.78,-0.33,P=0.020). The downward trend accelerated from 2013 to 2018, and the APC was -5.99 (95%CI:-7.52,-4.43,P<0.001). The trend of child mortality rate in rural area, females, eastern provinces of China, children aged 10 to 14 years, children aged 15 to 19 years, and injury mortality rate were basically consistent with the overall trend. The child mortality rate in urban area, central provinces of China and the mortality rate of infectious diseases, maternal and infant, and nutritional deficiencies diseases showed a uniform downward trend from 2004 to 2018, with AAPC values about -3.59 (95%CI:-4.38,-2.78,P<0.001), -2.89 (95%CI:-3.24,-2.54,P<0.001) and -6.66 (95%CI:-7.64,-5.68,P<0.001), respectively. Conclusion: The mortality rate of children and adolescents aged 5 to 19 years in China continues to decline from 2004 to 2018, and the decline rate becomes faster after 2011.