China’s 2009 health-care reform expanded Universal Health Coverage (UHC), but inequalities persist for internal migrants. Analysis of nearly one million migrants (2013–2018) showed high medical insurance enrollment (87.4%) and financial protection improvements, but lower access to essential health services such as health records (24.3%) and health education (75.7%), with growing inequalities in these areas. Both individual and regional factors drove disparities, suggesting the need for targeted policies to reduce inequities and strengthen access to basic health services for migrants.