Soil quality can be assessed by looking at the types and activity of microorganisms in the soil. Good quality soil has a stable community of microorganisms with high biomass and activity. This review looked at the composition, diversity, biomass, and activity of soil microorganisms to define key indicators of soil quality. To improve future research, it suggests standardizing methods for collecting, storing, and analyzing soil samples, studying the impact of subsoil microorganisms on soil quality, and creating a database of microbial attributes in different soils.