Fire is a crucial disturbance factor in desert ecosystem, which has significant effects on vegetation-soil system, playing a key role in ecosystem management. By the artificial burning in spring, this paper studied the effects of fire on the soil moisture and nutrient contents in a desertified steppe of Northwest China. The effects of the fire on the topsoil moisture content were related to precipitation events. The topsoil moisture content in burnt plots had an increasing trend at the stages of the frequent occurrence of precipitation, but decreased during the period of no precipitation. The soil total N and organic matter contents increased in the current year of burning, but decreased in the next year. Fire had no significant effects on soil total phosphorus and total potassium content and soil pH. These findings indicated the definite effects of fire on the soil physical and chemical properties in desertified steppe, and provided reference for the fire management of our desertified steppe.