Isolation and diagnosis of bacillus mucilagionsus bacteria was done from different location of the rhrizospher soils. The diagnosis included studying the microscopical and biochemical properties for these isolates. The laboratory study included testing the isolates efficiency of isolates for solubilize potassium compounds in liquid and solid media (Modified Aleksandrov agar medium) and determination of its solubility coefficient. Results of isolation and diagnosis for 19 samples of rhizosphere soil planted with different crops (wheat , barley and vegetable crops)showed that only 7 isolates were dissolve potassium compounds with different degrees .The results of microscopical test showed these 7 isolates were rod-shape, gram positive, capsulated spore former and motile. On the other hand, the results of biochemical tests which include Catalase test, urease test, utilization of Glucose, Voges proskauer test, H2S production, utilization of ornithine, Nitrate reduces enzyme production, phenylalanine deaminase production, Lysine utilization, Gelatinase test and oxidase test. In addition to cultural properties showed that these isolates belong to bacillus mucilaginosus .Results showed that these isolates differ in their potassium solubility index with the range 1.22 to 2.25 while the sugar in the media effect on these solubility and glucose gave the superiority.