Abstract: In this study, we separated and purificated the bacteria for releasing insoluble potassium from soil by a selective medium in which potash feldspar power was treated as the only source of potassium. We diluted the bacteria with gradient and lined on culture plate for separation and purification of the bacteria for release potassium, and used flame spectrophotometer to determine potassium content in nutrient solution, and then selected high efficiency bacteria. The results show that Klebsiella variicola, Enterobacte aerogenes, Enterobacter cloacae and Pantoea agglomerans were good for release available potassium from potash feldspar power. Therefore, these bacteria can be used as candidate strain for production of microbial fertilizer.