Abstract: Disclosed is a polymer for capturing or separating leukocytes. The polymer is prepared by a polymerization reaction of monomers containing an amino and a hydroxyl. The monomer containing an amino and a hydroxyl has the structure of formula (1): In formula (1), R1 is independently selected from the group consisting of a hydrogen, a methyl, an ethyl, a hydroxyl, any one of C1 to C12 long carbon chains, and a benzene ring, R2 is independently selected from the group consisting of a hydrogen, a methyl, an ethyl, any one of from C1 to C6 long carbon chains, an amino and a benzene ring, and n is an integer of 1 to 5.