Root exudates and litter inputs provide basic resources for soil food web. However, the effects of tree roots and litter on soil nematode communities in plantations with different tree species combination are still unclear. In September 2019, three artificial stands, e. g., Erythrophleum fordii Oliv. monospecific-planted forest, Pinus massoniana Lamb. monospecific-planted forest, and Erythrophleum fordii Oliv. and Pinus massoniana Lamb. mixed-species-planted forest, were selected to conduct a field manipulative experiment by removing roots and aboveground litter in Pingxiang, Guangxi Province. Soil nematode communities and soil properties were investigated in the plot of roots removal, litter removal, both roots and litter removal and corresponding control plots in March 2021. The results showed that roots removal altered nematode trophic group composition regardless the artificial stands by decreasing the relative abundance of fungivores and increasing the relative abundance of plant-parasites. Litter removal significantly decreased nematode total abundance, richness, nematode channel ratio and structure index, indicating that litter removal reduced the stability of soil food web. The results suggested that the input of tree roots, regardless artificial stands, was the main driving factor in shaping nematode trophic composition, and aboveground litter played an important role in maintaining the stability of soil food web. Furthermore, roots removal and litter removal had no significant impacts on soil nematode communities in E. fordii and P. massoniana mixed-species-planted forest, suggesting that the mixed forest with N-fixing tree species could facilitate the stability of soil food web compared to the pure conifer stand. Our findings highlight that introducing N-fixing tree species and mixing N-fixing species into pure conifer forests to enhance the plantation soil ecosystem stability.