Soil micro-food web organisms are considered to be a key link between below- and above-ground ecological processes. They are not only important drivers for the transformation, storage and release of soil nutrients, but also positive regulators for the plant-microbe relationships. Therefore, soil micro-food web organisms may have a greater impact on plant growth and soil nutrients than soil microorganisms which have received widespread attention. In this study, we detected the differential effects of soil micro-food web organisms and soil microorganisms on the growth of a peatland plant (Carex angustior) and soil nutrients. Three experimental treatments including soil micro-food web organism addition, soil microorganism addition, and sterilized soil were set up with 10 replicates for each. The soil micro-food web organisms were obtained by the extracted peat soil solution passing through a 45μm sterile microporous membrane (containing both soil microorganisms and nematodes), while the soil microorganisms were obtained by soil solution passing through a 22μm sterile microporous membrane (containing only soil microorganisms). The plant biomass, morphological and physiological plant traits, and soil nutrient contents were detected after 4 months of growth. The results showed that the total plant biomass and total plant nitrogen with soil micro-food web organisms were significantly greater than those of plants with soil microorganisms. There was no significant difference in plant biomass between the soil microorganisms and control treatments. Both the soil micro-food web organisms and soil microorganisms did not significantly alter plant height and root/shoot ratio. The root traits of C. angustiors were unaffected by the soil micro-food web organisms, but significantly affected by the soil microorganisms. The specific root length and the ratio of fine root length of plants with soil microorganisms significantly increased, and the root diameter decreased compared to the control plants. The soil available nutrient contents were also largely different among treatments. The soil available phosphorus content in the soil micro-food web organisms treatment was significantly lower than the other two treatments, while the soil soluble carbon content in the soil microorganisms treatment was significantly higher. No significant differences in the total carbon, nitrogen, and phosphorus content of the soil were detected among treatments in this experiment. Results from this study indicated that the soil micro-food web organisms are more beneficial than soil microorganisms to plant growth, and differently affect the morphological and physiological traits of plant and soil nutrient contents. This study provided new perspectives and reliable data for a deeper understanding of the importance of soil micro-food web organisms on plant growth and soil nutrient turnover, and for improving research on the processes and mechanisms of plant-soil biological interactions.