Abstract: Two types of soil covered by biological soil crusts (BSCs), i.e. moss and algae, and moving sand in the natural vegetation area at the southeast fringe of the Tengger Desert were collected intactly. They were incubated continuously for 20 days under two different temperatures (15 ℃ and 25 ℃) and moistures (10% and 25%) condition in the laboratory, and soil NO₃^--N contents were measured after 1, 2, 5, 8, 12, 20 days of incubation and net nitrification rate was evaluated during dehydration. The results showed that  NO₃^--N content of the mosscovered soil (2.29 mg·kg^-1) was higher than that of the algaecovered soil (1.84 mg·kg^-1) and sand (1.59 mg·kg^-1). Net nitrification rate of the three soil types ranged from -3.47 to 2.97 mg·kg^-1·d^-1. For the mosscovered soil and algaecovered soil at 10% and 25% moisture levels, the net nitrification rates at 15 ℃ were 75.1%, 0.7% and 99.1%, 21.3% higher than those at 25 ℃, respectively. Also, the net nitrification rates at 15 ℃ and 10% moisture levels were 193.4% and 107.3% higher than those at 25 ℃ and 25% moisture levels, respectively. The results suggested that regardless of soil moisture increasing or decreasing under the global warming senior, the net nitrification rate of BSCssoil system in the desert would probably be limited to some extent during drought process.