The effect of spatial non-integration between the administrative regions and economic zones in China has always existed， and administrative divisions have become an important means of spatial governance in recent years， laying the foundation for solving the problem of developing cross regional spaces with high-quality. The Beijing-Tianjin-Hebei agglomeration was used to study the spatiotemporal changes， spatial spillover effects， and mechanisms of driving land development intensity. The adjacency relationships between county-level administrative units were embedded into the spatial econometric model to further investigate the impact of administrative spatial spillover on land development intensity under different scenarios of spatial adjacency. The results showed that there was a significant difference in the land development intensity among administrative units within the Beijing-Tianjin-Hebei agglomeration， with significant spatiotemporal differentiation and spatial agglomeration. From a spatial perspective， the overall land development intensity in the Beijing-Tianjin-Hebei agglomeration had a significant upward trend， but the overall spatial pattern of "high in the southeast and low in the northwest" was not broken. Population density， the proportion of added value of the tertiary industry， and per capita GDP had a significant impact on the land development intensity. The correlation between the land development intensity and the spatial distribution was significantly positive and spatial， with obviously direct spatial spillover. The administrative spatial spillover of different adjacency relationships was different and the spatial spillover of adjacency scenarios of county-level administrative units was enhanced from 2010 to 2019. It is indicated that the administrative spatial spillover of land development intensity should be fully utilized to achieve balanced regional development in the future.