Abstract: A bacterial phytase cDNA was amplified with regular PCR technique and it contains 1360 bp encoding 423 amino acids with protein molecular size approximately 48 KDa. The cDNA fragment was sub-cloned into pEGFP-N3 plasmid DNA at the cloning sizes of BamH1/Pst1 .The recombinant pEGFP/ aPPA2 plasmid DNA were transfected into mammalian COS7 cells. The recombinant plasmid was expressed in the mammalian cells and the fusion proteins exhibited high phytase activity. This study provides a new system to produce phytase with a potential for an application in related industry.