[Objective] To explore the effects of plant communities and soil nutrients on the stability of soil aggregates on gully slopes in the gully region of the Loess Plateau, and to provide a theoretical basis for regional ecosystem restoration and sustainable vegetation reconstruction. [Methods] Four typical herb communities ( dominant species were Artemisia gmelinii, Artemisia argyi, Artemisia frigida and Stipa bungeana ) were selected as the research objects. Through field investigation and indoor analysis, the variation of plant diversity, root, soil nutrient characteristics and water-stable aggregate composition with soil depth was studied. [Results] ① Artemisia argyi community had the highest species diversity, Patrick richness index and Shannon-Wiener index were significantly higher than those of other communities, while its Simpson index was the lowest. There was no significant difference in Pielou evenness index among the communities. ② The root length density and root mass density of each community decreased significantly with the increase of soil depth, and the RLD and RMD of the surface layer ( 0~20 cm ) were 2.71~10.80 times that of the deep layer. ③ Soil organic carbon, total nitrogen and stoichiometric ratios decreased significantly with soil depth, while total phosphorus did not change significantly. The SOC, TN and TP contents of Artemisia argyi community were significantly higher than those of other communities in each soil layer, and their average values were 1.07~1.84 times that of Artemisia gmelinii community, 1.12~1.43 times that of Artemisia frigida community and 1.14~2.81 times that of Stipa bungeana community. ④ The proportion of > 0.25 mm water-stable aggregates and aggregate stability indexes ( MWD and GMD ) in Artemisia argyi community were significantly the highest, which were 1.15~1.55 times and 1.27~2.98 times that of other communities, respectively. Partial least squares path model showed that soil nutrients were the strongest direct driving factor for aggregate stability ( path coefficient 0.850, P < 0.01 ). Root distribution indirectly affected aggregate stability by significantly increasing soil nutrient content ( path coefficient 0.817, P < 0.01 ) ( indirect effect 0.695 ). [Conclusion] Higher species diversity promotes soil nutrient accumulation through developed roots, thereby synergistically enhancing the formation and stability of soil aggregates through the ' root-soil nutrient ' pathway.