The content and proportion of each form of potassium was analyzed from 16 representative soil samples derived from four soil parent materials in Hunan tobaccogrowing areas.The results showed that the soil derived from purple slate parent material showed larger potassium storage capacity and lower available potassium content,indicating a limit ability to effectively maintain soil potassium;The soil derived from limestone parent material showed the smaller quantity of mineral potassium and a relatively higher content of nonexchangeable and available potassium.The limited potassium storage capacity and potential for selfcompensation of soil available potassium and a high level of soil available potassium of soil from quaternary red clay parent material might have close relations with potassium application.There was only 27% nonspecifically absorbed potassium that with high availability in exchangeable potassium content in soils developed from different parent materials which might directly limit the shortterm soil potassium supply intensity level.The availability of potassium varied with parent materials,in order of limestone>board of shale>the quaternary clay>puple shale.