People’s exposure to blue-green spaces decreased but inequality increased during 2001–2020 across major Chinese cities

• We proposed an improved model to assess people’s exposure to blue-green spaces. • Quantify the contributions of different components by ecosystem services value. • Chinese exposure to blue-green spaces was low and continued to decline. • Chinese exposure exhibited a extremely high level of inequality and worsening. • Low exposure was more urgent in the North, while high inequality was in the South. Sufficient and equitable exposure to blue-green spaces enhances human well-being. Existing studies on people’s exposure to blue-green spaces have not adequately considered the different contributions of various components in the blue-green spaces. We proposed an improved model to estimate people’s exposure to blue-green spaces and inequality by distinguishing the contributions of blue-green space components via ecosystem services value. The results showed that people’s exposure to blue-green spaces in Chinese cities was low (0.067). Spatially, the exposure was higher in the south and lower in the north, while higher in the west and lower in the east. Compared with 2001, the exposure declined by 23% in 2020. Additionally, the spatial distribution and the component configuration of the blue-green spaces were not reasonable. Meanwhile, the exposure among the population exhibited extremely high inequality, with an average Gini coefficient of 0.845. During 2001–2020, the overall inequality continued to worsen (+3%). The intensification trend demonstrated spatial differences, with a more pronounced pattern in eastern cities. Further research confirmed that inequality existed among different genders and age groups. Finally, spatial correlation analysis showed that cities with high exposure and equality tended to be in southern China. Low exposure was more pronounced in northern cities, and inequality was a more pressing issue in southern cities. We hope this study can provide a reference for blue-green space planning and boost the sustainability of cities.