Abstract: Microplastics (MPs) are prone to form compound pollution problems with multiple pollutants during the long-term migration and transportation of various environmental media. In response to this problem, this study selected polymethyl methacrylate (PMMA) as the representative of MPs, and levofloxacin (LEV) as the representative of antibiotics. Batch adsorption experiments were carried out to study the adsorption behavior of LEV onto PMMA, and the influence of various environmental factors on its adsorption behavior was discussed. Research results show that the adsorption kinetic process of LEV onto PMMA conforms to the pseudo-second-order model. The adsorption rate is affected by both internal and external diffusion. The adsorption process is mainly physical adsorption. The enrichment capacity of LEV onto PMMA with five different particle sizes is as follows: 1 μm>75 μm>125 μm>250 μm>500 μm. The actual seawater environment has a significant inhibitory effect on adsorption capacity of LEV onto PMMA, which is only 14.5% of the simulated freshwater environment. Environmental factors such as ionic strength, humic acid both have a certain degree of influence on adsorption behavior. This study can provide theoretical support for the research of interface behavior of antibiotics by MPs, and provide theoretical guidance and research basis for the compound pollution of emerging pollutants in the environment.