Abstract: Microplastics are ubiquitous in the environment, possessing the ability to adsorb environmental pollutants such as heavy metals and organic pollutants, while also engaging in a variety of complex interactions with these pollutants. These interactions alter the environmental tendencies and toxic effects of these pollutants. Based on a review of the interaction mechanisms between microplastics and organic pollutants, heavy metals, and binary composite pollutants, this article analyzes the influencing factors and the dual effects brought about by composite pollutants. The interaction mechanisms between microplastics and pollutants mainly include distribution and surface adsorption, with the latter further subdivided into hydrophobic effects, electrostatic effects, hydrogen bonding, Van der Waals forces, chelation, and π-π interactions. The interactions are mainly influenced by physicochemical properties of microplastics and pollutants themselves and environmental factors. The carrier effect of microplastics can enable both itself and other environmental pollutants to infiltrate organisms, thereby inducing biological effects. However, according to current research, besides instigating toxic effects in organisms, composite pollutants also have positive aspects that need further exploration. Lastly, this article points out deficiencies in existing research and looks forward to future research trends, with the aim of providing references and assistance for future research on microplastics.