Litter accumulation affects growth of plant species by redistributing hydrothermal condition in fenced steppe ecosystems. To explore the ecological adaptations of different plant species with diverse morphological and ecological characteristics to litter accumulation, we conducted a litter removal experiment in a fenced typical steppe in Inner Mongolia during 2015-2017. Soil temperature and moisture were continuously monitored in situ. The growth and quantitative characteristic of the dominant and subdominant species (Stipa grandis and Leymus chinensis) were measured. The results were as follows. Litter accumulation significantly decreased surface and deep soil temperature (1.3-4.6 ℃ in surface soil and 1.5-3.2 ℃ in deep soil) but remarkably increased surface and deep soil moisture (1.4%-10.4% in surface soil and 1.0%-5.0% in deep soil). Litter accumulation delayed the returning greening day of S. grandis (16.9-24.2 days) more than that of L. chinensis (5.2-6.7 days) but had no significant effects on their vegetative period. Litter accumulation significantly increased the height of S. grandis but decreased its cover and aboveground biomass, which remarkably reduced the important value of S. grandis (0.38→0.22). Conversely, litter accumulation significantly increased the height, cover, and aboveground biomass of L. chinensis, which remarkably increased its important value (0.16→0.28). Comprehensively, the order change of important value in S. grandis and L. chinensis drove community succession in the fenced steppe. This study elucidates the changes of community structure and function in fenced steppe ecosystems from the perspective of plant population and provides the theoretical basis for scientific and rational formulation of enclosing policy.