The anthropogenic release of reactive nitrogen (Nr, consists of all nitrogen species except N₂) from urban food consumption contributes to national nitrogen-related pollution. The emergence of food nitrogen footprint indicator, which quantifies the amount of reactive nitrogen release to the environment by food production and consumption, can address the potential environmental impacts on urban surroundings to feed the increasing population of a city with rapid urbanization. In this study, a modified N-Calculator model was developed to calculate the food nitrogen footprint of Shenzhen City from 2010 to 2015, the typical immigrant city with higher degree of urbanization in China. The related spatio-temporal variations in regional food nitrogen footprints within the city and their relationships with urbanization were then analyzed. The results showed as follows: (1) the food nitrogen footprints caused by different types of urban residents per capita presented variations. The trend in average food nitrogen footprints of urban permanent resident presented growing from 14.63-15.17 kg N per capita, which exceeded 13.09 kg N per capita of urban non-registered resident during study period, mainly due to the differences in daily consumption of meat, fruit and aquatic products. These data revealed the gradually strengthening of the gap between permanent and impermanent urban residents' food nitrogen footprints. (2) The entire food nitrogen footprint of Shenzhen City increased by 11.50% in 5 years, which was driven by growth of food nitrogen footprints produced by urban permanent residents, while urban non-registered residents' food consumption was the main contributor to current urban food nitrogen footprint. The variations in regional food nitrogen footprints within Shenzhen City presented spatial heterogeneity and aggregation, and the growths of those generated from the internal administrative districts and subdistricts were significantly different. The hotspots of food nitrogen footprints growing in the scale of subdistrict mainly located in the western coastal regions in Shenzhen City, the growths of their footprints were partially exceeded the magnitude of those created by some administrative districts. (3) The study found that there were no obvious relationships between the increases in urban food nitrogen footprints and population urbanization within the city, but to some extent correlations between smaller-scaled footprints and economic urbanization were witnessed. Current trends in immigrant population settlement and the personal preference for high nitrogen diet post barriers to further reductions in urban food nitrogen footprints, and the alleviation in the upstream reactive nitrogen loss from food production is the key measure for Shenzhen City to contribute to the sustainable development of Guangdong-Hong Kong-Macao Greater Bay Area.