Background: China has achieved spectacular success in reducing child mortality since 1949. The health workforce is thought to have been important in this progress, but a thorough understanding of how the health workforce contributes to lowering child mortality is lacking. This PhD aims to examine the declines in child mortality in China over the past seven decades and to understand how the health workforce contributes to that progress. Methods: I did a systematic review to understand the profile and density of the maternal and child health workforce in China since 1949, and a scoping review to evaluate national trends in and determinants of child mortality between 1949 and 2019. I analysed longitudinal data between 1950 and 2017 to examine the speed of decline in child mortality and to investigate the strength of association between doctor density and child mortality in 1950-1964, 1965-1980, and 2000-2016. Results: In 1950, child mortality was very high in all provinces - one out of five infants died in the first year of life and three out of ten children died before reaching age five. Both infant mortality and child mortality aged 1-4 declined by more than 90% across all provinces between 1950 and 2017. The most rapid decline in child mortality occurred between 1950 and 1955. Increased density of doctors, though not highly educated compared to international standards, contributed to lowering child mortality in China during 1950-1964, independent of economic growth. But in 1965-1980 doctor density was positively associated with child mortality after adjusting for socio-economic, environmental and health system determinants of child mortality. The association disappeared in 2000-2016. Conclusion: The rapidly decreased child mortality in the early period can give other countries - particularly the poor countries confidence that progress is possible through efforts to scale up the production of health workers. Improving doctor density alone is unlikely to achieve further progress in reducing child mortality in China.