Display omitted •Little is known about the regional and socioeconomic disparities in PM2.5-mortality burden in China.•We provided data of PM2.5-related mortality burdens for 296 Chinese cities during 2015–2019.•There were significant regional and socioeconomic disparities in PM2.5-related mortality burdens.•Different regions and socioeconomic groups may need different mitigation policies. Quantifying the spatial and socioeconomic variation of mortality burden attributable to particulate matters with aerodynamic diameter ≤ 2.5 µm (PM2.5) has important implications for pollution control policy. This study aims to examine the regional and socioeconomic disparities in the mortality burden attributable to long-term exposure to ambient PM2.5 in China. Using data of 296 cities across China from 2015 to 2019, we estimated all-cause mortality (people aged ≥ 16 years) attributable to the long-term exposure to ambient PM2.5 above the new WHO air quality guideline (5 µg/m3). Attributed fraction (AF), attributed deaths (AD), attributed mortality rate (AMR) and total value of statistical life lost (VSL) by regional and socioeconomic levels were reported. Over the period of 2015–2019, 17.0% 95% confidence interval (CI): 7.4–25.2 of all-cause mortality were attributable to long-term exposure to ambient PM2.5, corresponding to 1,425.2 thousand deaths (95% CI: 622.4–2,099.6), 103.5/105 (95% CI: 44.9–153.3) AMR, and 1006.9 billion USD (95% CI: 439.8–1483.4) total VSL per year. The AMR decreased from 120.5/105 (95% CI: 52.9–176.6) to 92.7/105 (95% CI:39.9–138.5) from 2015 to 2019. The highest mortality burden was observed in the north region (annual average AF = 24.2%, 95% CI: 10.8–35.1; annual average AMR = 137.0/105, 95% CI: 60.9–198.5). The highest AD and economic loss were observed in the east region (annual average AD = 390.0 thousand persons, 95% CI: 170.3–574.6; annual total VSL = 275.6 billion USD, 95% CI: 120.3–406.0). Highest AMR was in the cities with middle level of GDP per capita (PGDP)/urbanization. The majority of the top ten cities of AF, AMR and VSL were in high and middle PGDP/urbanization regions. There were significant regional and socioeconomic disparities in PM2.5 attributed mortality burden among Chinese cities, suggesting differential mitigation policies are required for different regions in China.