Abstract: In this paper it deseribes the preparation and properties of the encapsulated arthrobacter simplex cells.by liquid surfactant membrane which catalyzes the transformation of biger steroid molecule,i.e.,corlisol into prednisolone.The experimental results indicated that the catalytic transformation take place very well and in some system the encapsulated cells keep the initial rate of catalytic transformation as good as that of the free cells.By encapsulation it raises the stability of stroragc.We also investigated various factors which affected the biocatalytic transformation from which we knew that the encapsulated cells system was not influenced by the contaminaljon of Bacillous cells which inhibited the free cells system seriouslv.