In order to provide the basis for ecological construction in the area of grassland, we studied the effects of enclosure and level trench ecological restoration on soil biological characteristics in the Hilly Loess Plateau Gully steppe. Using the method of space gradient instead of time gradient, in typical steppe in the loess hilly area of Ningxia, we selected soils in areas which included the unenclosed (grazing), enclosed for 3-15 years, the level trench after 1-15 years, analyzed the change characteristics and relationship of the number of microorganisms, soil microbial biomass nitrogen and carbon, and soil enzyme activity the in 0-10 cm, 10-20 cm, 20-30 cm, and 30-40 cm soil layers. The results showed that: (1) Soil microbial community in the test area was dominated by actinomycetes, which accounted for 86.18-94.43%, and the overall order was actinomycetes > bacteria > fungi; the amount of soil microorganisms, the number of bacteria and actinomycetes, microbial biomass carbon and nitrogen, urease, protease, phosphatase, sucrase activity all showed an upward change with the increase of enclosure ages, but they all showed an up-down-up trend in level trench; on the contrary, the change of soil catalase activity had a opposite trend in both the enclosure and level trench, and the number of fungi was lower in FY6 and SP6, being 11.33 cfu/g and 4.67 cfu/g, respectively. (2) Under different treatments, in the 0-40 cm soil layer, microbial and enzyme activity in the upper soil was higher than in the underlying soil. The correlations between soil microorganism, enzyme activity and contents organic matter and main nutrients were significant (p < 0.05); (3) Within the similar recovery period, the number of soil microorganisms, microbial biomass carbon and nitrogen, and enzyme activity were generally higher in the enclosed grassland (p < 0.05). Our research showed that, compared with level trench, enclosure was more conducive to increase soil microorganisms and enzyme activities in typical steppe of the Loess Hilly Area.