A field experiment substitute a space series method for a time course method, was conducted in a degraded typical grassland in Balinyou County, Inner Monglia. The objective of the experiment is to reveal the process of natural ecological restoration of grassland after removed human activities by fencing. The results indicated that species diversity dynamically changed during the process, with the highest value of 3.3 at the 6th year, and declined afterward. Both relationships between species richness and species diversity index and species uniformity and the later were significant (p<0.05) with correlation coefficients of 0.848 and 0.912 respectively. Instead, the relationship between aboveground biomass and species diversity was not significant with correlation coefficient of 0.4813 (P>0.05). Through restoration process, the prominent roles of some species in plant community alternatively changed significantly, that C4 species played an important role at the early stage, but C3 species occurred necessarily to stabilize the community at the late stage. Also, the annual species took an important role at early stage of the typical grassland restoration process, such as covering land surface, preventing soil erosion, recycling nutrients into community, and producing a better soil condition for other species’ surviving.