Hydroxyapatite [Ca10(PO4)6(OH)2] is an inorganic pure phase chromatography resin, which is calcined into spheres at high temperature. Its crystal structure is the same as that of bone hydroxyapatite; the spherical structure is stable and the particle size is uniform. There are multiple modes of interaction between hydroxyapatite and biomolecules, which can achieve two separation mechanisms of cation exchange and calcium metal affinity simultaneously. The cation exchange mainly depends on the negatively charged phosphate groups on hydroxyapatite. At the same time, carboxyl clusters and phosphorus clusters on biomolecules can form with calcium on hydroxyapatite through a metal-affinity, stronger bond. Due to these unique separation mechanisms, hydroxyapatite is an indispensable chromatographic resin in today’s extremely demanding downstream processes in antibodies, vaccines (such as bacterial polysaccharides, pneumococcal polysaccharides and viruses), nucleic acids, enzymes and recombinant proteins, playing an important role in the field of biopharmaceuticals.