Abstract: Five-year-old Ziziphus jujuba Mill. cv. Lingwuchangzao trees were used as materials, and ¹⁵N trace technique was used to study the effects of 0 kg/plant （CK）, 0.5 kg/plant （T1）, 1.0 kg/plant （T2） and 1.5 kg/plant （T3） potassium fulvic acid organic fertilizer on nitrogen absorption, distribution and utilization of Z. jujuba Mill. cv. Lingwuchangzao in the field experiment. The results showed that the nitrogen accumulation of Z. jujuba Mill. cv. Lingwuchangzao increased with the increase of fulvic acid potassium supply level. The nitrogen accumulation of T3 was the highest （59.66 g/plant） at fruit maturity. The nitrogen accumulation of leaves and fruits was high in each treatment. The three fulvic acid potassium treatments significantly improved the nitrogen absorption and regulation ability （Ndff values） and ¹⁵N absorption of plants（P<0.05）, and the order from high to low was T3, T2, T1, and CK. In terms of the Ndff value of different organs, the value of the fruit was the highest. The ¹⁵N distribution rate of each organ of plants with different treatments was different, and the storage organ （fruit） was high. Compared to CK, the ¹⁵N utilization rates of three fulvic acid potassium treatments increased by 2.27 to 5.34 percentage points, and T3 was the best （8.92%）. Comprehensive analysis showed that the ¹⁵N absorption and utilization of Z. jujuba Mill. cv. Lingwuchangzao was the best, when combined with fulvic acid potassium organic fertilizer of 1.5 kg/plant.

Key words: fulvic acid potassium, Ziziphus jujuba Mill. cv. Lingwuchangzao, nitrogen, absorption, distribution, utilization