NOVELTY - An immobilized micro-organism is prepared by preparing carrier material solution comprising 1-1.5% sodium alginate solution and 9-12% polyvinyl alcohol solution; placing immobilized microorganism in the carrier material solution to form microorganism mixing solution; adjusting pH value of the mixing solution; performing immobilization reaction of micro-organism ball for 0.5-1 hour; washing the microorganism with distilled water; performing another immobilization reaction; and washing and fetching out the microorganism ball and washing it with distilled water up to three times.    USE - Method for preparing an immobilized micro-organism for use in wastewater biological treatment, biological pharmacy, food fermentation, and brewing industry.    ADVANTAGE - The method is simple and can be operated continuously. It uses polyvinyl alcohol and sodium alginate as embedding materials; replaces boric acid in traditional method with sodium sulfate and does the immobilization reaction in two steps through calcium chloride and sodium sulfate. There is nearly no sticking in the preparing process of fossilizing micro-organism and there is no toxicity. The reaction reagent and condition have little influence on the cell activity. The prepared immobilized micro-organism has high strength and good stability.    DETAILED DESCRIPTION - Preparation of immobilized micro-organism comprises:    (A) preparing carrier material solution comprising 1-1.5% sodium alginate solution and 9-12% polyvinyl alcohol solution at mass ratio of 1:6-12;    (B) placing immobilized microorganism in the carrier material solution at mass ratio of 1:4-6 to form microorganism mixing solution;    (C) adjusting pH value to 6.5-6.7 by adding calcium chloride solution containing 1-1.5% sodium hydrate solution;    (D) adding calcium chloride solution into the microorganism mixing solution to do first immobilization reaction of micro-organism ball for 0.5-1 hour;    (E) washing the microorganism up to three time with distilled water;    (F) placing the microorganism in saturated solution for another immobilization reaction for 2-4 hours; and    (G) washing and fetching out the microorganism ball and washing it with distilled water up to three times.