[Objective] Soil nitrogen transformation is a microbially-mediated biogeochemical process that though strongly influenced by global climate change, is an effective indicator of soil. Nitrogen supplying capacity and soil nitrogen availability of a terrestrial ecosystem. Therefore, the study of characterizing soil nitrogen transformation helps to thoroughly and deeply understand the productivity and nitrogen cycling process in an ecosystem. Biocrusts, making up over 40% of the total area of the land surface cover in the arid region, is an important type of earth surface cover in desert, and a major compositions of the desert surface landscapes in the semi-arid and arid regions as well, so it plays a vital regulatory role in nitrogen cycling in arid area. This study aimed to explore responses of nitrogen transformation rate, microbial biomass carbon and nitrogen and enzyme activity in the crust-covered soil system to global warming, and reveal mechanisms of the responses from different levels (functional gene→microbial biomass→enzyme activity) in an attempt to provide a theoretical basis for studies in future to identify ecological functions of moss crusts in soil nitrogen cycling in temperate desert ecosystems under the background of climate warming.[Method] This study explored responses of soil nitrogen transformation rates, microbial biomass, enzyme activities and functional genes to warming in temperate desert ecosystems with undisturbed soil columns with moss crust cover on the surface collected from the field.[Result] Results show that soil net nitrogen transformation rates (net ammoniation rate, net nitrification rate and net nitrogen mineralization rate), enzyme (N-acetyl-β-D-glucosidase and urease) activities, abundance of microbial biomass carbon/nitrogen transformation function genes (gdh, hao and amoA) responded significantly to warming and soil type, and interactions between the two were apparent. Compared with CK, warmed moss covered soil was 49.5%, 63.2%, and 59.7%, respectively, lower in net ammonification rate, net nitrification rate, and net nitrogen mineralization rate and lower in enzyme (N-acetyl-β-D-glucosidase, leucine aminopeptidase and urease) activities. Microbial biomass carbon and nitrogen, and in abundance of ureC, hao and amoA, too (gdh exclusive). Moss crust covered soil was higher in net nitrogen transformation rate, enzyme activity, microbial biomass carbon and nitrogen, and nitrogen transformation function gene abundance than mossless soil under the same treatment.[Conclusion] To sum up, warming significantly inhibits soil nitrogen transformation process by decreasing enzyme activity, microbial biomass, and functional gene abundance, while degradation of the moss crust weakens its role in regulating the soil environment, thus accelerating the process.