Microplastic contamination of the marine environment has become a global environmental problem. Because of their small dimensions, microplastics can easily interact with a wide range of marine organisms, enter their bodies in various ways, and accumulate in and transfer between their tissues and organs, which results in toxic effects. Absorption and ingestion of microplastics, primary by lower trophic-level organisms, can be transferred along the marine food chain, threatening marine ecosystem health and stability. For this reason, the interaction between marine organisms and microplastics, and the ecological effects of marine microplastic pollution have become hotspots for current studies. Based on the review of biofouling of marine organisms on the microplastic surface, ingestion of microplastics, toxic effects of microplastics on marine organisms, and the combined toxic effects of microplastics with other chemical contaminants, this study proposed that future research on the ecological effects of microplastic pollution should focus on marine organism ingestion of microplastics in the marine environment of China, biological effects and toxicological mechanisms of microplastics on organisms, combined effects of microplastics with other contaminants, and the functions of microplastics in the marine ecological system and their biogeochemical behaviors.