Growing health inequalities have become an important challenge for Chinese society. This study analyses the impact of negative childhood experiences on health among Chinese adults over 45. Data were derived from the 2014 Life Course Survey under the China Health and Retirement Longitudinal Study, with a total sample of 5,842 adults over the age of 45. The results showed that negative childhood experiences had a significant negative impact on the health of adults over 45 ([beta] = -0.021, p < 0.001). The concentration index decomposition revealed that negative childhood experiences were associated with more health inequalities. The elasticity coefficient for negative childhood experiences was -0.119, the concentration index of negative childhood experiences was -0.019, and the contribution to health inequalities was 12.86%. The mechanism test and analysis found that negative childhood experiences had a greater negative impact on the health of the low-income group than on that of the high-income group. Therefore, health inequality should be viewed from life course theory. To reduce residents' health inequalities, government's decision-making should be forward looking and start early in life; interventions should be pursued in residents who have had unfortunate childhood experiences.