The estimation of crop nitrogen content at the field scale by using Unmanned Aerial Vehicle（UAV） images has attracted increasing attention due to their nondestructiveness and time-effectiveness. The black soil region of Northeast China is the main agricultural production base in China， and accurately obtaining crop nitrogen content is of great significance for national food security. In this study， the Leaf Nitrogen Content（LNC） of maize was estimated by the stepwise regression method using UAV hyperspectral images and 22 narrowband spectral indices at the jointing， silking， and maturity growth stages of maize. The results showed that the maize LNC estimation models at the three growth stages all had good performance. Moreover， the estimation accuracy of the model at the maturity stage was slightly higher than those from the other two stages， with R²， RMSE， and nRMSE values of 0.76， 0.31%， and 0.15%， respectively. The estimation model at the silking stage had the lowest accuracy， with R²， RMSE， and nRMSE values of 0.33， 0.27%， and 0.19%， respectively. At the same time， the spectral indices that can indicate maize LNC were obtained. They were VARI （Vegetation Atmospherically Resistant Index）， DDI （Desertification Difference Index） and EVI （Enhanced Vegetation Index） at the jointing stage； MTCI （MERIS Terrestrial Chlorophyll Index） and SIPI （Simple Insensitive Pigment Index） at the silking stage； and EVI （Enhanced Vegetation Index）， CCI （Canopy Chlorophyll Index） and NDVI （Normalized Difference Vegetation Index） at the maturity stage. Finally， the spatial distribution map of maize LNC was obtained using the model with the highest estimation accuracy at each growth stage， and its spatial distribution characteristics were consistent with the actual maize LNC conditions. However， the amount of nitrogen fertilizer had a greater impact on the maize LNC among the microplots with different treatments. The results of this study can provide a database and decision support for the nondestructive， rapid and dynamic monitoring of maize leaf nitrogen content in the black soil region of Northeast China.