The porous structure of calcium phosphate ceramics is one of the essential conditions resulting in bone formation. The porous structure of biphasic HA/β-TCP ceramics was improved by adding microporous porosifer and the porous characteristics such as porosity, pore size and pore size distribution were determined by the mercury intrusion porosimetry, the cell culture in vitro and the animal experiment. By means of SEM and fluorescence decoration, cells were observed firstly attaching the edge of macropores of specimens and the wall of the macropores with micropores when co-cultured with HA/β-TCP ceramics. The specimens were also implanted in dorsal muscles of healthy dogs for 1.5and 3 months. More bone formation in the specimen with microporous porosifer was found by histological observation after taking out. It suggested that the micropores in the walls of macropores of bioceramics had important effect upon their osteoinduction.