The invention relates to the field of blood purification, in particular to a bilirubin adsorbent directly prepared through a hydrothermal method, and application of the bilirubin adsorbent. The specific preparation process comprises the steps: water is taken as a solvent, glucose is taken as a carbon source, methylacryloyl propyl trimethyl ammonium chloride is taken as a functional reagent, a quaternary ammonium group is introduced, and then the adsorbent with excellent hydrophilcity can be prepared only through a one-step reaction. The adsorbent has a good removal effect on the pathogenic factor, namely bilirubin of hyperbilirubinemia.