Abstract: When the original pH value of the penicillium's culture fluid was 5.5,the phytase was produced much .While the pH of culture fluid didn't decrease, the growth of penicillium could be inhibited. Calcium phytate could promote the penicillium to increase phytase activities.Two isoenzymes of phytase from penicillium were accepted by ammonium sulfate precipitation,sephadex G-100 gel filtration chromatography. The purification factors of phytase reached 3.3 folds with a specific activity of 71 3 U/mg.