The urease activities and physico-chemical properties of nineteen samples collected from seven main soils in Shaanxi Province were analyzed. The results obtained by the correlation, path and principal component analyses showed that the soil urease activities varied significantly with the soil fertility level and soil physical and chemical properties had both direct and indirect influences on the urease activity. Similar evaluation results of soil fertility were got by using an information system of soil ertility consisting of principal component and by the urease activities and the physical and chemical properties respectively.