The ecological effect of atmospheric N deposition has become a hot issue along with intensive human activities and global climatic change. N deposition can result in a great change of ecosystem's structure and function, leading to a serial of ecological effects. In this article we reviewed the ecological consequence of N deposition in arid and semi-arid ecosystem as follow: (1) the characteristic of N deposition in arid and semi-arid area is that the nitrogen enters into the N cycle in a form of pulse, impacting other ecological processes. (2) N deposition can increase the mineralization of organic nitrogen and the content of inorganic N in the soil. N cycle can also be affected by other factors. (3) N deposition has a positive effect on the metabolic activity of microbe in soil, and there are still some argues on the effect on microbial biomass. (4) N deposition can influence plant productivity, root growth, although these effects are also regulated by water availability. (5) N deposition can reduce the abundance of endemic species and is benefit to the invasion of exotic species.