The present disclosure provides a brush polymer, including: a linear polymer main chain; and brush structural side chains, including: a hydrophobic molecular branch, and a hydrophilic molecular branch and/or an anti-biofilm/or an anti-microbial molecular branch, wherein the linear polymer main chain is conjugated to the side chains by covalent bonds formed between a hydroxyl group and a reactive functional group, wherein the reactive functional group includes: isocyanate, carboxyl, or epoxy. The present disclosure also provides a medical application of the brush polymer.