In order to find out the best nitrogen application, the effects of different nitrogen applications（0, 50, 200,350, 500, 650, 800 g/plant） on the photosynthetic characteristics and yield of Zizyphus jujube Mill. Lingwuchangzao were studied. The chlorophyll content, transpiration rate, stomatal conductance, photosynthetic rate, single fruit weight, single plant fruit setting and yield of Lingwuchangzao increased and then decreased with the increase of nitrogen application, and reached the maximum value at 350 g/plant. Compared with the control, the chlorophyll content, transpiration rate, stomatal conductance and photosynthetic rate increased by 8.3%, 21.6%, 77.5%, 20.6%, respectively, the intercellular CO₂ concentration decreased by 7.6%, and single fruit weight, single plant fruit setting,yield increased by 8.2%, 31.5%, 42.7%, respectively. According to the regression equation between nitrogen application and yield, the recommended nitrogen application is 355.89 g/plant. This study provides a theoretical basis for the application of nitrogen fertilizer in Lingwuchangzao planting area with medium fertility.