BACKGROUND: China is one of the few Countdown countries to have achieved Millennium Development Goal 5 (75% reduction in maternal mortality ratio between 1990 and 2015). We aimed to examine the health systems and contextual factors that might have contributed to the substantial decline in maternal mortality between 1997 and 2014. We chose to focus on western China because poverty, ethnic diversity, and geographical access represent particular challenges to ensuring universal access to maternal care in the region. METHODS: In this systematic assessment, we used data from national census reports, National Statistical Yearbooks, the National Maternal and Child Health Routine Reporting System, the China National Health Accounts report, and National Health Statistical Yearbooks to describe changes in policies, health financing, health workforce, health infrastructure, coverage of maternal care, and maternal mortality by region between 1997 and 2014. We used a multivariate linear regression model to examine which contextual and health systems factors contributed to the regional variation in maternal mortality ratio in the same period. Using data from a cross-sectional survey in 2011, we also examined equity in access to maternity care in 42 poor counties in western China. FINDINGS: Maternal mortality declined by 8·9% per year between 1997 and 2014 (geometric mean ratio for each year 0·91, 95% CI 0·91-0·92). After adjusting for GDP per capita, length of highways, female illiteracy, the number of licensed doctors per 1000 population, and the proportion of ethnic minorities, the maternal mortality ratio was 118% higher in the western region (2·18, 1·44-3·28) and 41% higher in the central region (1·41, 0·99-2·01) than in the eastern region. In the rural western region, the proportion of births in health facilities rose from 41·9% in 1997 to 98·4% in 2014. Underpinning such progress was the Government's strong commitment to long-term strategies to ensure access to delivery care in health facilities-eg, professionalisation of maternity care in large hospitals, effective referral systems for women medically or socially at high risk, and financial subsidies for antenatal and delivery care. However, in the poor western counties, substantial disparity by education level of the mother existed in access to health facility births (44% of illiterate women vs 100% of those with college or higher education), antenatal care (17% vs 69%) had at least four visits), and caesarean section (8% vs 44%). INTERPRETATION: Despite remarkable progress in maternal survival in China, substantial disparities remain, especially for the poor, less educated, and ethnic minority groups in remote areas in western China. Whether China's highly medicalised model of maternity care will be an answer for these populations is uncertain. A strategy modelled after China's immunisation programme, whereby care is provided close to the women's homes, might need to be explored, with township hospitals taking a more prominent role. FUNDING: Government of Canada, UNICEF, and the Bill & Melinda Gates Foundation.