Abstract: The aim of this study was to evaluate the responses of grassland plant species diversity and the aboveground biomass of several common plant species to microbial fertilizer. We set up a factorial experiment to test the interactive effect of six microbial fertilizers in the Leymus chinensis meadow steppe in Hulunbuir in August 2014-2016. The seven treatments were as follows: control (CK), humic acid (F), alginic acid (H), fermented molasses (T), humic acid+fermented molasses+alginic acid (F+H+T), humic acid+compound microbial inoculant (F+J), and alginic acid+compound microbial inoculant (H+J). The results showed that addition of F and H from 2014 to 2016 did not significantly affect plant communities. Addition of F+H+T in 2014, 2015, and 2016 increased plant density by 26.72%, 17.92%, and 34.64%, respectively, and increased aboveground biomass by 7.18%, 49.97%, and 47.64% respectively. Addition of F from 2014 to 2016 did not significantly affect the plant community, but addition of T, H, F+H+T, and H+J increased the importance of the Gramineae and Leguminosae. Rhizome-type grasses (L. chinensis) showed greater responses to compound microbial fertilizers than did clonal grasses and rosettle grasses. Addition of F in 2014, 2015, and 2016 decreased the Margalef index by 16.40%, 5.22%, and 37.22%, respectively. Addition of H in 2014-2016 did not affect the diversity index, but addition of F+H+T in 2014-2016 increased the Margalef index, the Shannon-Wiener index, and the Pielou index. Addition of H+J in 2014 to 2015 increased the Pielou index by 7.62% and 8.70%, respectively. These results show that application of microbial fertilizer can significantly affect the plant community, species diversity, and aboveground biomass in the Hulunbuir L. chinensis meadow steppe. The combination of F+T+H had the strongest effect to increase plant community species diversity and aboveground biomass. Precipitation should also be taken into consideration in the restoration of grassland resources.