For preparation and purification of Streptavidin, two synthetic mediums and a procedure for purifying Streptavidin were studied. We found that Streptomyces avidinii grew vigorously and showed typical colony characterization. At the sametime, these synthetic mediums were in favour of producing Streptavidin with a maximal production of 15.2 micrograms/ml by using DEAE 52 column for purification of Streptavidin. This purification procedure is very simple and easy, and could be widely used.