Abstract: 【Objective】 In order to reveal the nitrogen catalysis and assimilation capacity of Salicornia europaea L. seedlings under nitrogen application in salt environment, and to deeply understand the mechanism of the grass to nitrogen uptake and transformation. 【Method】 The pot experiment method was used to study the effects of different nitrogen application levels on the key enzyme activities of nitrogen assimilation of Salicornia europaea L. seedlings growing under salt environment. 【Results】 The results showed that, compared with the treatment without nitrogen application, under severe salt environment conditions, nitrogen application increased the activities of roots, stems, assimilated shoots NR, GS, GOGAT, GLDH of the plant. Under N 1.2 g/kg, the NR activity, GS, GOGAT activity of the root, stem, and assimilated branches of Salicornia europaea L. seedlings reached their maximum values; When N (2.4 g / kg) was applied, the roots and assimilated branches of GS, GOGAT activity and GLDH activity of root, stem and assimilated branches reached the maximum. 【Conclusion】 Nitrogen application in salt environment can significantly enhance the key enzyme activities of nitrogen assimilation of Salicornia europaea L. seedlings, increase its ability to nitrogen stress, thus enhancing its adaptability to high nitrogen environment.