Abstract: Microplastic pollution has caused global environmental problems, among which the problem in the marine environment is particularly prominent. Rivers flowing into the sea are important channels for the interaction between land and ocean. Most of the land-based materials migrate into the sea through rivers. Therefore, the water quality of the rivers and the amount of pollutants transported have become the hot issue of the impact of land on the ocean. This paper summarizes the studies on the flux and abundance of microplastics from rivers to sea on a global scale in recent years through systematic investigations. Recent studies have estimated that the flux of land-sourced microplastics accounts for 64% to 90% of the total plastic debris in the marine environment, and the total amount of plastic fragments (microplastics and large plastics) transported by global rivers to the ocean each year is 0.41×10⁶-4×10⁶ t. However, whether the global model is applicable to a specific basin still needs to be corrected and tested. From a methodological point of view, collecting microplastic abundance data is the basic prerequisite for studying the flux of microplastics from rivers to the sea, and the current lack of unified monitoring and analysis research methods makes it difficult to visually compare the fluxes of different rivers. Coupled with insufficient actual measurement data, the land-source analysis and quantitative research of microplastics in rivers entering the sea are still in the preliminary stage. Future research should focus on data optimization methods that highly couple microplastics transportation and river flow, and clarify the migration and transformation mechanisms of microplastics in the process of rivers entering the sea based on hydrodynamic models. In addition, extensive and close international cooperation should be carried out on a global scale, a unified research system should be established, and the basic database information for global microplastics research should be continuously completed, so as to promote the international community to jointly deal with microplastics pollution.