Abstract: Soil nitrogen (N) pool and its' cycles is directly related to crop growth, ecological environment security, and sustainable development. Soil N and carbon storage in natural ecosystems is relatively stable, with a low net mineralization and a closed or accumulative cycle. In order to meet the demand from the growing population for food production and living space, humans frequently modify natural ecosystems, resulting in changes to land use and ecological cover, which significantly change the soil active N content and N cycles, thereby affecting global climate change and the natural environment. In the face of threats from global warming, reduction of biodiversity, and ecological degradation, this paper reviewed the impact of soil active N on the environment, N storage, and N cycling process, including mineralization, nitrification, and fixation, caused by land use change. We considered the transformation, deforestation, afforestation, or reconstruction of ecosystems, as well as progress in research methods on microorganisms in the N cycle. Our review showed that agricultural reclamation or disturbance — the conversion of natural ecosystems into farmland or the abandonment of farmland that was originally forest or grassland — would lead to a significant decrease in total N, but an increase in the nitrate (NO₃^--N) content, which increases the risk of active N in the environment. Reforestation provides an alternative approach for the reconstruction of ecological cover, but full restoration of the N pool will take decades. It seems that the application of modern microbial molecular ecology is the key to research the response mechanism of the soil N cycle to ecological cover/land use change. The aim of this review was to provide a scientific basis for the protection and use of native ecosystems, the restoration and reconstruction of degraded ecosystems, scientific planning and policy-making for artificially disturbed ecosystems by understanding the effects of land use change on the soil N pool, coupled N cycling, and the soil microbial community structure.