Five nitrogen fertilizer treatments:0 kg/hm²(CK)，150 kg/hm²(T1)，300 kg/hm²(T2)，450 kg/hm²(T3)，600 kg/hm²(T4)were set up in this experiment，and the same amount of potassium fertilizer(150 kg/hm²)and phosphorus fertilizer(60 kg/hm²)were also applied to explore the effects of different nitrogen fertilizer applications on the fruit quality of Lingwu long jujube and the change trend of soil nitrogen content with the increase of nitrogen application rate.The results showed that the vitamin C content，single fruit weight and sugar-acid ratio of Lingwu long jujube fruit increased first and then decreased with the increase of nitrogen application rate，and reached the maximum value under T2 treatment. Compared with the control，the vitamin C content，single fruit weight and sugar-acid ratio of Lingwu long jujube treated with T2 increased by 17.27%，15.94% and 10.90%，respectively.When the nitrogen application rate was above 150 kg/hm²，the soil nitrogen content at maturity increased with the increase of fertilizer application rate，and the soil nitrogen content of T2 treatment increased the least compared with the initial nitrogen content，indicating that T2 treatment met the needs of Lingwu long jujube plants while minimizing the impact on the soil nitrogen content.Using principal component analysis，the four principal components extracted covered 92.687% of the original information，and the T2 treatment had the highest score. To sum up，the best nitrogen application rate of Lingwu long jujube is 300 kg/hm²，which can not only improve the fruit quality of Lingwu long jujube，but also provide a theoretical basis for scientific fertilization of Lingwu long jujube.