<p>Biomineralization of natural composites are usually highly finely adjusted to achieve extremely precise control over the shape, size and distribution of inorganic crystals, giving them unique structures and properties of biomaterials. These underlying mechanisms and pathways provide inspiration for the design and construction of materials for repairing hard tissues. Due to good biocompatibility of hydrogels, materials using gel-like systems as media are inextricably linked to biological macrocomponents and mineralization. Inspired by those bioprocesses, polyacrylamide hydrogel with enzymes was 3D printed to form controlled shapes and structures, then was used as templates for mineralization. Effect of polyacrylamide hydrogel pore size on the mineralization was studied via incorporating NaF and CaCl₂ and controlling the mineralization degree. The mineralization processes of 3D printed hydrogels with different pore sizes were also explored to find out the confinement influence of pores. Mineralization in hydrogels with smaller pores is developed in a columnar stacked pattern, which is similar to the vesicular mineralization stage of bone mineralization.</p>