Abstract: Plastics widely exist and accumulate constantly in various marine environments of coastal and even pelagic waters seas. The environmental persistence of plastics and their detrimental impacts on both marine ecosystems and the human health have attracted public attentions. In this paper, we reviewed the recent advances in marine microplastics (MP) study from two sides, the MP in marine ecosystem and the MPdegrading microorganisms. In general, MP widely distribute in various marine environments, especially in estuary, coastal waters, sediments, beaches and oceanic circulation centers. Currently reported plasticdegrading microorganisms are mainly isolated from terrestrial soil, plastic waste recycle and landfill sites, and the wellstudied degraders are related to the decomposition of polyethylene terephthalate (PET). Recently in China, the marine surveys on MP distribution, abundance and ecotoxicological effects extend from coastal areas to pelagic oceans, even deep trenches and polar regions. However, the knowledge on MPdegrading bacteria is very limited. It is urgent to improve our understandings of MP fate in marine environments, especially in deep sea and their interactions with marine bacteria that live on plastics. MP investigations should be encouraged to integrate MP survey and marine microbiology to efficiently evaluate MP influences on marine ecosystem.