A biocompatible inorganic porous material having a three-dimensional coexistent network of interconnected macro-pores and nanopores produced by the steps of mixing an organic water-soluble polymer (e.g., polyethylene oxide or a block copolymer of ethylene oxide and propylene oxide), an alkoxysilane, and an inorganic water-soluble calcium salt in an aqueous acid solution, such that a sol-gel process of hydrolysis and polycondensation is initiated and thereby producing a gel; drying the gel to remove solvent by evaporation; and heating the gel to remove the polymer by thermal decomposition, thereby forming an inorganic porous material, which may be suitable for use as a bone tissue scaffold.