Vegetation recovery in the Loess Plateau of China has been identified as the most effective and useful way to alleviate soil erosion and degradation. This study was to examine the responses of soil microbial indicators to natural vegetation rehabilitation on the Loess Plateau. Soil samples at the depths of 0-20 cm and 20-40 cm were collected from the Yunwu mountain grassland area with an recovered chronosequence of 0, 3, 9, 15, 23, 58, 73, and 78 years. The results showed that microbial biomass C (MBC) was increased significantly along with vegetation rehabilitation time increasing. In the early 23 years revegetation sites, the increasing MBC rate was 24.1% and 104.4% every year at 0-20 cm and 20-40 cm, respectively. However, after 23 years of revegetation, the increasing rate of MBC was only 0.83% and 0.19% at 0-20 cm and 20-40 cm every year, respectively. Soil MBN also increased faster during the first 23 years with increasing rates of 20.14% and 15.11% at the 0-20 cm and 20-40 cm every year, respectively. Soil basal respiration (SBR) increased gradually during the vegetation natural succession. The qCO2 decreased with a logarithm functional trend with the enclosed time increaseed. Compared to soil respiration intensity, the qCO2 reflected the change of microbial activity more clearly and consistently. The MBC, MBN and SBR had a positive relationship with soil organic carbon, available nitrogen and clay contents, but they had a negative relationship with soil silt content. In addition, soil pH at the surface layer also affected the soil microbial properties. These research results reinforced the notion that natural succession of grassland has altered positively soil microbial communities and activities in the surface layer, provided indications that vegetation restoration can have positive impacts on soil microbial quality on the Loess Plateau.