The use of phosphate solubilizing microorganism to dissolve phosphate content of phosphate ore instead of conventionally methods is an ecologically safe and economically reasonable. The objective of the present study is to study the factors affecting on dissolution of phosphate content in Abu Tartur phosphate ore by using fungus.The serial dilution method was performed to inoculums solutions to achieve microorganisms isolation which obtaining one fungus that has ability to dissolve phosphate ore and is identified by 18 sRNA as Aspergillus niger. The optimum conditions of bioleaching of Abu Tartur phosphate ore were 7 days incubation period at glucose-yeast extract medium, 2x106 SFU of A.niger for 50 ml medium, 0.5% Abu Tartur phosphate ore incubated at 30 °C. different carbon and nitrogen sources were evaluated which peptone was the best nitrogen source, glucose the best carbon source, the best diameter of conical flask base for bioleaching process was above 4.5 cm , no significant effect of addition factor, also there was decreasing in pH and increased in redox potential, initial pH 6, shaking flask is at 150 rpm. The efficiency of A. niger for phosphate content dissolution of Abu Tartur phosphate ore by applying all optimum conditions was 100%.