Ecological effects mainly refer to the damage to the environment caused by various anthropogenic activities. These usually cause structural and functional change in the ecosystem. With the increased use of plastics, plastic pollution has become a very important part of environmental pollution management. Their ecological effects and prevention have been the focus of pollution prevention in recent years. Plastics are difficult to degrade in the environment, and after the physical effects of weathering, they eventually form plastic particles less than 5 mm in diameter called microplastics. This has led to the ecological effects and degradation methods of microplastics receiving much attention in recent years. In addition to plastic waste pollution, the use of disposable plastic products, plastic film, and other plastic agricultural materials can also cause microplastic pollution in the soil. Microplastics in the soil will expand the pollution scope by lateral and vertical migration. Lateral migration mainly refers to the diffusion of microplastics in the surface layer of soil through wind and surface water, while vertical migration refers to the diffusion of microplastics to deeper layers of soil through soil organisms, water or various enrichment methods. The migration of microplastics increases the degree of microplastic pollution in soil and creates a great challenge for soil microplastic management. In this review, the ecological effects of microplastics are reviewed in terms of soil environment, soil microorganisms, plant, and food chain. The deposition of microplastics in plants and food chain is discussed, and the risk of microplastic enrichment along the food chain is analyzed. The ecological effects of soil microplastics come from three main sources:the main components of the plastic, additives in the plastic synthesis process, and the pollutants that the microplastic absorbs from the environment. Microplastics can directly change the physicochemical properties of soil, affect the function and structure of soil microbes, and accumulate in plants, thereby affecting their health. Also, microplastics can enter the animal and human bodies through diet, drinking water, and respiration. Additionally, soil microplastics can be dispersed into the air by way of dust lifting and thus be inhaled by animals at different levels of the food chain through respiration. Once inside the organism, microplastics may enter the circulatory system of the organism and thus accumulate in various parts of the organism. Microplastics have been found in many livestock products, but their entry channels into animals still need to be studied. Even though the content is very low, these microplastics may accumulate in the human body in large quantities through the food chain. The biodegradation methods of microplastics, especially the degradation mechanisms of fungi and bacteria are discussed in detail. Currently, studies have found that insects, bacteria and fungi in soil can degrade microplastics, and all of these organisms could also be good countermeasures to deal with soil microplastic pollution. Finally, based on the summary of the existing research on ecological effects and biodegradation of microplastics, the review analyzes and outlooks the future research directions and priorities of soil microplastics.