Evaluation of belowground impacts of methods of invasive plant eradication, especially in the context of grassland restoration, gives information about rates of ecosystem restoration. This study tested the hypotheses: (1) the method of seed application and plant species diversity used in grassland restoration impacts on mesofauna communities, (2) the mowing regime influences the abundance of soil invertebrates. A two-factorial experiment using: (1) different methods of seed introduction and composition (sowing the seed mixture of pasture grasses, pasture grasses with legumes, seed collected from a semi-natural meadow, and application of fresh hay), and (2) different frequencies of mowing (once, twice and three times per year), was established during the restoration of grassland which had been invaded by Solidago plants. The experiment was designed as a randomized complete block design with four replications. The results were revealed that mowing intensity decreased the abundance of Chilopoda and Isopoda, while the introduction of fresh hay used in grassland restoration positively affected nematodes. Also, the biological soil quality index based on arthropods (QBS-ar) indicated a decrease of soil biological quality in stands mown 2 and 3 times in comparison to mowing once. Further studies are needed to investigate the soil mesofauna dynamics exposed by mowing, and plant diversity.