Nematodes are recognized as key indicators of soil health and essential components of soil food webs. Litter input serves as the primary energy and nutrient source for the soil food webs. Global climate change has significantly affected the quantity of plant litter input in recent years. This study, conducted from January 2018 to May 2023, explored the effects of litter removal and addition on the community structure and metabolic footprint of soil nematodes in a Robinia pseudoacacia forest on the Loess Plateau. The aim was to provide a scientific foundation for the sustainable management of artificial forests in the northwest region under future climate scenarios. This experiment included four treatments: no litter, natural litter, double litter, and triple litter input. The results showed that litter input significantly affected the abundance, ecological indexes, and metabolic footprint of soil nematodes. Under the triple litter treatment, the abundance of soil nematode reached 1705 nematodes per 100 g dry soil, which was the highest among the four treatments. Compared to the control treatment, the nematode abundance increased significantly by 76.25%, while the species richness index decreased by 27.11% under the triple litter treatment (P < 0.05). The maturity index, Wasilewska index, total nematode metabolic footprint, and fungivores metabolic footprint significantly increased with the amount of litter, while the relative abundance of plant parasitic nematodes and the plant parasitic index decreased (P < 0.05). Correlation analysis revealed that the abundance of soil nematodes and the total nematode metabolic footprint were significantly positively correlated with soil water content. The species richness index was negatively correlated with soil microbial biomass carbon content. Additionally, the relative abundance of plant parasitic nematodes and the plant parasitic index were negatively correlated with dissolved organic carbon content. Redundancy analysis indicated that soil microbial biomass carbon content, available nitrogen, and dissolved organic carbon were key environmental factors affecting soil nematode communities. These findings suggested that excessive litter input simplified nematode food resources, thereby reducing species diversity. However, excessive Robinia pseudoacacia litter input provided sufficient organic matter resources and a suitable soil habitat, enhancing nematode abundance and metabolic activities. Particularly, increased litter input inhibited the growth and reproduction of plant parasitic nematodes, which, in turn, could diminish the negative impact of plant parasitic nematodes on the soil ecosystem and enhance soil health. The results elucidate the response mechanisms of soil ecosystem to litter input and predict soil health under future climate conditions in the Robinia pseudoacacia forest on the Loess Plateau.