A medical macromolecular microsphere adsorbent for a blood perfusion apparatus and a preparation method thereof are provided. The polystyrene-divinylbenzene microspheres are graded by different pore sizes and specific surface areas, medically purified, and grafted by a bioactivity-controlled grafting technology. In the microsphere adsorbent, the volume ratio of microspheres with pore sizes of 1-10 μm, 10-100 μm and 100 μm is 1:(1-10):(1-20), the content of residual monomers in the microsphere has O.D190-400 nm≤；0.03. The microsphere adsorbent not only can adsorb harmful micromolecules in blood but also can effectively adsorb harmful medium-molecules and macromolecules in blood, thereby meeting clinical application demands.
