Viruses are non-cellular biological entities, simple in structure, composed of proteins outside and nucleic acids inside. The total number of virus-like particles (VLPs) in the Earth biosphere was estimated about 4.80×10³¹, which is overwhelmingly higher than that of organisms with cellular structure therein. Soil is an important reservoir of viruses, consisting mainly of bacteriophages (phages) that are able to infect prokaryotes. Metadata analysis shows that the number of the viruses in soil is closely related to the number of their host cells and certain soil physical and chemical properties. Although researchers in this aspect have realized that the viruses in soil may play an important role in regulating composition of soil microbial communities, thus influencing recycling of soil elements, promoting microbial evolution, and affecting the health of animals and plants, as well as human beings. However, due to high adsorbability of the soil virus particles and heterogeneity of the soil, as well as the limitation of research methods and analysis platforms, the cognition of and the attention paid to the viruses in soil in the current researches lags far behind those in the environments of flowing waterbodies, like river, oceans, etc.. Among the soil viral metagenomes, a huge number of genes remain undetermined in sequence, source and function and hence are sorted into the catalogue of unknown genes. Consequently, viruses in soil are deemed as biological ‘dark matter’ and the largest unexploited gene treasure trove. In this paper, a brief introduction to morphology, abundance, existing form and diversity of the viruses in soil, a review of the methods and their limitations in using molecular marker genes, random amplified polymorphic DNA-PCR and metagenomic analysis techniques to parse diversity of the viruses in soil, and then discussions about validated and potential ecological functions of the viruses were presented. In the end, directions of the researches in future on viruses in soil that should be strengthened were brought forth, stressing the importance of coupling studies on soil viruses and soil microorganisms in future studies to reveal ecological functions of the soil.