Abstract: With the dramatic increase in the amount of plastic waste in marine and freshwater environment, the microplastic content in freshwater lakes in cold regions, represented by Lake Ulansuhai, has increased significantly. Ice formation during the freezing period will promote the enrichment of microplastics in the ice cover. In order to deeply understand the environmental migration characteristics of microplastics in cold and frozen regions, a self-made icing device was used to simulate the freezing and thawing periods of lake water, to reveal the influence of microplastics on the growth rate and melting rate of ice thickness, and ice density. The results showed that the existence of microplastics could promote ice growth, and the ice thickness growth value showed a trend of increasing first and then decreasing with the increase of microplastic abundance. Microplastics played an obstructive role in the melting of the ice, and with the increase of microplastic abundance, the obstructive role was more obvious. Observations of the density of ice samples under different conditions revealed that the change in ice density was dominated by the abundance of microplastics and the freezing temperature, while the particle size of microplastics had a slight impact, which was a combined effect. The microplastics abundance and icing temperature affected the process of ice formation and melting, as well as changes in the ice density.