Abstract:The characteristics of nitrogen metabolism and soil nitrogen of four invasive plants (Ipomoea cairica, Wedelia trilobata, Synedrella nodiflora, Lantana camara) and one native plant (Paederia scandens, control plant) had been studied. The results showed that the activity of nitrate reductase in invasive plant tissue, the contents of NH4-N and NO3-N and the activities of protease and urease in their rhizosphere soil were higher than those of Paederia scandens by 1.65~4.34 times, 1.56~2.15 times, 1.72~3.11 times, 1.43~3.23 times and 1.41~3.33 times, respectively. But the nitrate content in invasive plant tissue fell to 17.5%~50.6% that of Paederia scandens. Furthermore, the correlation analysis indicated that the activity of nitrate reductase in invasive plant tissue was positively and significantly related to total nitrogen, NH4-N, NO3-N and the activities of protease and urease in their rhizosphere soil. The invasion of exotic plants speeded up nitrogen metabolism, enhanced nitrogen bioavailability, improved the efficiency of nitrogen assimilation, and coordinated plant nitrogen metabolism with soil nitrogen metabolism. All these benefited their growth when invasive plants competed against native ones for nitrogen, which might be a contributing factor to their successful invasion.