This research is to optimise the best nutrition condition of the phytase-producing strain (Spicaria Harting 26-13-4) which is from the black soil growing soy bean in Hailun City, Heilongjiang Province. The D-saturation and optimization design are carried out on the added amount of carbon, nitrogen and bran on the ferment substrate. The equation is made according to the three material then the best added amount can be confirmed.