Abstract: Due to extensive production, use and discharge, antibiotics continue to be released into the aquatic environment and are frequently detected as emerging contaminants in surface waters. Seasonal freeze-thaw of water bodies is a common natural phenomenon in mid and high latitudes, and antibiotics have been detected in frozen rivers and reservoirs. To reveal the ice-water distribution of the antibiotic ciprofloxacin (CIP) in frozen water, the simulation experiments were conducted on the top-down natural freezing process of static water bodies. It was found that CIP was redistributed between the ice and water phases. Due to the freezing-concentration effect, only a small amount of CIP was trapped in the ice, while the majority of CIP was released from the ice and migrated to the water under the ice, resulting in a clear ice-water distribution pattern of CIP. The initial CIP concentration, freezing temperature, freezing time and salinity affected the ice growth rate, solute diffusion rate and ice structure, thereby altering the distribution of CIP in the ice-water system. The increase in salinity hindered the migration of CIP to the water under the ice. During the ice melting process, the compact structure of the ice was destroyed under the external heat, and the ice cracks increased so that the CIP showed early elution. In conclusion, the ice-water distribution pattern of CIP is greatly influenced by environmental factors, and the concentration in water under ice is significantly higher than that in ice, and CIP will be preferentially released when ice melts. The results of this study contribute to understanding the distribution and migration of antibiotic pollutants in frozen water in cold regions, and provide a basis for accurately evaluating the risk of pollutants in subglacial waters.