In this study the kinetic properties of dissolving phosphorus by the phosphobacteria 9320-SD is reported using the powdered phosphorite as a reactive material. The samples were treated with H2SO4-H2O2 for the whole phosphorus assay. The plant-available phosphorus in the samples was determined by a photometer. Living microorganism cells were numbered in colony-forming units by cultivating on solid media. The results indicated that the rate of product forming had a direct ratio relation with the growing rate of phosphobacteria 9320-SD and its cell density. The kinetic equation of dissolving phosphorus by the phosphobacteria 9320-SD is X dt dP =αμ , and the kinetic equation of transforming plant-nonavailable phosphorus to plant-available phosphorus is Y = 4.54lg x +11.23.