Two kinds of tri-calcium phosphate ceramics, β-TCP, which have the same macrostructure and microstructure, but different special surface area and particle size, were used in porous ceramics. A slip was obtained by adding the powders to a solution 1.0 wt% of deflocculant, respectively. The specimen obtained by casting a polyurethane foam with 0.5wt% into a slip, and drying it under vacuum, was heated at 1150, for 3 hours. The porous ceramics samples about 0.5g were individually soaked into 30 mL of phosphate buffer saline (PBS) at 20 for 1,3,7 and 10 days, respectively. The calcium content of the PBS solution was analyzed by (ICP). The porous bodies were filtered, dried, and characterized using SEM, XPD, and FT-IR.