Objective: To explore whether Integrated Early Childhood Development (IECD) program has effectively improved the nurturing care for children aged 0-35 months in rural China. Methods: IECD has been implemented by the government of China with support from the United Nations Children's Fund (UNICEF) in four poverty-stricken rural counties since 2014. The interventions targeting the five key components of nurturing care (i.e. child and caregiver health, child nutrition, early learning support, child protection and social security) were delivered through the IECD program to children aged 0 to 35 months and their caregivers. A population-based intervention trial was designed to evaluate intervention effectiveness with data collected in 2013 (baseline) and 2016 (mid-term). The changes of nurturing care in the intervention and control group were analyzed by using a difference-in-differences (DID) model. This approach provided adjustment for sociodemographic and other confounding factors. Results: The baseline and mid-term survey enrolled 1 468 and 1 384 children in the intervention group, and 1 485 and 1 361 in the control group. After two years of implementation, the prevalence of caregiver's depression in the intervention group showed a decrease of 9.1% (mid-term 34.8% (479/1 377) vs. baseline 43.9% (621/1 414)), whereas that in control group showed a decrease of 1.6% (mid-term 34.3% (464/1 353) vs. baseline 35.9% (509/1 419)). With the confounding adjusted in the difference-in-differences model, the decrease of the caregiver's depression prevalence in the intervention group was 7.0% greater than that in the control group (P=0.008). The qualified rate of minimum meal frequency in the intervention group showed an increase of 10.4% (mid-term 69.0% (532/771) vs. baseline 58.6% (481/821)), whereas the qualified rate in the intervention group showed an increase of 2.9% (mid-term 66.4% (469/706) vs. baseline 63.5% (508/800)). With the confounding adjusted in the difference-in-differences model, the increase of the qualified rate in the intervention group was 8.2% greater than that in the control group (P=0.021). The proportion of violent discipline by caregivers in the intervention group showed a decrease of 6.2% (mid-term 49.1% (478/973) vs. baseline 55.3% (554/1 001)), whereas the proportion in control group showed an increase of 4.5% (mid-term 58.4% (560/959) vs. baseline 53.9% (558/1 036)), and with the confounding adjusted in the difference-in-differences model, the difference in increase rate between two groups was 11.0% (P=0.001). The proportion of families with three or more children's books in the intervention group showed an increase of 12.7% (mid-term 42.7% (588/1 378) vs. baseline 30.0% (432/1 440)), whereas the proportion of the control group showed an increase of 4.2% (mid-term 25.7% (349/1 357) vs. baseline 21.5% (298/1 388)), and with the confounding adjusted in the difference-in-differences model, the difference in increase rate between two groups was 6.1% (P=0.007). Conclusions The IECD intervention strategy implemented in rural China effectively improved the mental health of caregivers, optimizes families' child feeding and early stimulation behaviors, while reducing violent discipline and other risk factors. IECD provides better nurturing care for the early development of children aged 0-35 months in rural China.