This study investigates the adsorption of five antibiotics (sulfadiazine, amoxicillin, tetracycline, ciprofloxacin, and trimethoprim) on five types of microplastics (polyethylene, polystyrene, polypropylene, polyamide, and polyvinyl chloride) in both freshwater and seawater systems. Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD) analyses revealed that microplastics have different surface characteristics and degrees of crystallinity. The adsorption isotherms showed that polyamide (PA) had the strongest adsorption capacity for antibiotics, with distribution coefficients (Kd) ranging from 756±0.257 to 756±48.01 L/g in freshwater, attributed to its porous structure and hydrogen bonding. Other microplastics exhibited relatively lower adsorption capacities. The adsorption amounts of the antibiotics on polystyrene, polyethylene, polypropylene, and polyvinyl chloride decreased in the order of ciprofloxacin > amoxicillin > trimethoprim > sulfadiazine > tetracycline, with Kd values positively correlated with octanol-water partition coefficients (Log Kow). In seawater, the adsorption capacity was significantly lower, and no adsorption was observed for ciprofloxacin and amoxicillin. The results indicate that polyamide particles can serve as a carrier of antibiotics in aquatic environments, highlighting the potential for long-range transport and compound combination effects.This study investigates the adsorption of five antibiotics (sulfadiazine, amoxicillin, tetracycline, ciprofloxacin, and trimethoprim) on five types of microplastics (polyethylene, polystyrene, polypropylene, polyamide, and polyvinyl chloride) in both freshwater and seawater systems. Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD) analyses revealed that microplastics have different surface characteristics and degrees of crystallinity. The adsorption isotherms showed that polyamide (PA) had the strongest adsorption capacity for antibiotics, with distribution coefficients (Kd) ranging from 756±0.257 to 756±48.01 L/g in freshwater, attributed to its porous structure and hydrogen bonding. Other microplastics exhibited relatively lower adsorption capacities. The adsorption amounts of the antibiotics on polystyrene, polyethylene, polypropylene, and polyvinyl chloride decreased in the order of ciprofloxacin > amoxicillin > trimethoprim > sulfadiazine > tetracycline, with Kd values positively correlated with octanol-water partition coefficients (Log Kow). In seawater, the adsorption capacity was significantly lower, and no adsorption was observed for ciprofloxacin and amoxicillin. The results indicate that polyamide particles can serve as a carrier of antibiotics in aquatic environments, highlighting the potential for long-range transport and compound combination effects.