Abstract: As two types of pollutants in Marine environment, microplastics can adsorb antibiotics in water and act as carriers for their migration, which can cause greater harm to the marine environment and marine organisms. The interaction of antibiotics with different microplastics not only differs, but the adsorption capacity and mechanism have not been deeply and clearly concluded. In this study, polyethylene (PE), polypropylene (PP), polyamide (PA), ultraviolet aging polyamide (PA^UV) and ultraviolet and H₂O₂ co-aging polyamide (PA^UV+H) were chosen as objects, and the adsorption capacity and adsorption stability of cefradine (CE) were investigated by density functional theory (DFT) calculation. The results show that the adsorption of CE on PE, PP, PA, PA^UV and PA^UV+H belongs to physical adsorption, and the adsorption stability of PA, PA^UV and PA^UV+H is stronger than that of PE and PP. For the adsorption mechanism between these three types of PAs and CE, electrostatic interaction plays a more important role, making their adsorption of CE more stable. In addition, the calculation results based on thermodynamic properties indicate that the adsorption of CE by MPs at T=273-311 K and P=1-1000 atm is a spontaneous exothermic process.