The relationship between urbanization and the ecological environment is not conclusive in the literature. We used the provincial data from China from 1998 to 2019 to empirically study the relationship between the urbanization ratio and ecological environment which is proxied by the NDVI (normalized difference vegetation index) from the remote sensing data. The results indicate that the coefficient of the interaction between urbanization and per capita GDP is statistically significant and negative (−0.0946), while the coefficient of urbanization itself is very trivial and not statistically significant. It implies that urbanization could reduce ecological quality, particularly for the high-income regions. The higher the urbanization ratio is, the larger the negative impact is. It implies that urban expansion does reduce the ecological environment. The effect of economic development level on the NDVI can be divided into three stages: the one where the NDVI improves with the increase of GDP per capita (urbanization rate of less than 77.59%), the one where the value of the NDVI is not affected by the level of GDP per capita (urbanization rate equal to 77.59%), and the one where the NDVI decreases with the increase of GDP per capita (urbanization rate of more than 77.59%).

Food security is pivotal for national sustainable development. This study utilizes panel data from 31 Chinese provinces spanning from 1990 to 2021 to construct distinct indicator systems for urban–rural integration and food security. The entropy method is employed to assess levels of urban–rural integration and food security, with their inter-relationship examined through a fixed-effects model. Additionally, this study conducts rigorous robustness and endogeneity tests, alongside comprehensive heterogeneity analyses across various dimensions and regions. The findings underscore the significant role of urban–rural integration in enhancing food security, particularly within spatial, social, and economic dimensions, albeit encountering challenges in ecological integration. Moreover, the impact of urban–rural integration on food security manifests differently across diverse food-producing regions, exhibiting notable advantages in primary production and distribution hubs while being negligible in balanced regions. These results accentuate the critical necessity for refining urban–rural integration strategies to bolster food security. Consequently, in formulating agricultural regional policies, careful consideration of resource allocation and the developmental stages of each region is imperative to ensure food security and promote sustainable agricultural practices.