Biodegradable plastics are increasingly recognized as a viable alternative to conventional plastics, offering a potential solution to persistent plastic pollution. However, the efficiency of their biodegradation and the subsequent ecological impacts have garnered significant attention. These biodegradable plastics primarily consist of biodegradable polymers with minor quantities of additives such as plasticizers, dyes, photo-stabilizers, etc., to obtain greater performances and some specific physicochemical properties or functionalities. The degradation of biodegradable plastics in soil consists of three phases： biodeterioration, bio-depolymerization, and bioassimilation coupled with mineralization. These processes are decisively influenced by the properties of the biodegradable plastics, while they can face interference from the biotic and abiotic factors of the soils. During degradation, substantial quantities of microplastics, additives, oligomers, and monomers are released into the soils, which can easily be ingested by soil animals and consequently pose more serious negative effects on the behavior, growth, and reproduction of soil animals. Furthermore, biodegradable microplastics can act as carriers of soil pollutants such as heavy metals and organic pollutants, resulting in soil combined contaminations and inducing more serious detrimental effects on soil organisms. Finally, the prospects for further studies in this field are put forward.