Abstract: As increasing attention has been paid to below-ground ecosystems in recent years, the impact of exotic plant invasions on soil ecosystems has emerged as a central issue in invasion ecology. In this paper, effects of exotic plant invasions on soil biota and soil nutrient cycling processes are reviewed, and the mechanisms that underlie these impacts are discussed. The available literature suggests that no consistent pattern exists on the impacts of exotic plant invasions on soil microbes, soil animals, soil carbon cycling and nitrogen cycling. The mechanisms underlying the impacts of exotic plant invasions are also complex and diverse. The discrepancies most likely arise from the differences between invasive and native plants in a variety of physiological and ecological traits, such as litter quality and quantity, root distribution, and phenology. Future studies are recommended to (a) compare the impacts across multiple scales and multiple ecosystems; (b) intensify mechanical studies of the impacts; (c) link the impacts on biodiversity and ecosystem processes; and (d) explore the mutualistic interactions between soil ecosystems and exotic plants.