In this paper, on the theoretical basis of pore volume distribution function which was measurable in laboratory, the novel distribution model concerning about some parameters including total pore specific surface area and total pore specific volume was given to successfully simulate pore volume, surface area and length, and that a subsequent the calculating result of pore volume distribution was compared with experimental result. It was found that for a full characterization of pore size distribution of calcium-based sorbents, it was feasible to employ this distribution model.