Urban greenspace plays a crucial role in urban ecosystems by enhancing environmental quality and promoting public health. The equitable distribution and accessibility of greenspace have garnered increasing attention, particularly in light of the varying developmental trajectories of cities. This study investigates greenspace exposure and its distributional equity across growing and shrinking cities, particularly focusing on the middle reaches of the Yangtze River Urban Agglomeration. We employed the normalized difference vegetation index (NDVI) and population data to measure greenspace exposure and used the Gini coefficient to quantify inequality levels. Our findings reveal significant differences between growing and shrinking cities regarding greenspace coverage, exposure, and equity. First, the average greenspace coverage across the studied cities was approximately 0.35, indicating a generally low level of urban greenery. Shrinking cities, with a mean greenspace coverage of 0.355, exhibited slightly better performance compared to growing cities, where the mean coverage was 0.344. Despite this marginal difference in coverage, shrinking cities consistently demonstrated better greenspace exposure and more equitable distribution patterns. For instance, shrinking cities showed a Gini coefficient of 0.468, significantly lower than the 0.544 recorded in growing cities. This implies that greenspace resources in shrinking cities are distributed more evenly, enhancing the overall environmental quality for residents. By contrast, growing cities tend to exhibit more severe inequalities in greenspace exposure, with the average inequality level being 1.16 times higher than in shrinking cities. These disparities can be attributed to market forces that prioritize land value in growing cities, often leading to the underprovision of greenspace unless actively mitigated by administrative planning or policy interventions. Furthermore, approximately 24% of the cities studied had Gini coefficients exceeding 0.6, indicating extreme inequality. These findings suggest that unchecked population and land use expansion in growing cities exacerbate greenspace inequity, which could be mitigated through targeted planning efforts such as green infrastructure integration and land-use regulations. This research highlights the need for urban policymakers to prioritize improving greenspace distribution, especially in growing cities, where market pressures may lead to the marginalization of greenspace. Meanwhile, in shrinking cities, strategies such as the greening of brownfields and underutilized spaces could further enhance urban sustainability and equity. In conclusion, this study underscores the critical relationship between urban development models and greenspace distribution patterns, providing a foundation for differentiated planning and policy interventions aimed at achieving balanced and sustainable urban growth. Future research should focus on expanding this analysis to a national scale and incorporating more comprehensive metrics for greenspace quality, including distinctions between natural and artificial greenspace.