NOVELTY - A method involves cultivating acetobacter xylinum in a thermostatic incubator to prepare cyanoethyl bacteria cellulose. The prepared cellulose is dipped into tetra-alkyl ammonium chloride solution. Acrylonitrile and alkalis solution are added to the cellulose and reacted for 30-120 minutes at room temperature. The mixture is washed and vacuum dried. The prepared cellulose is added to hydroxylamine (NH2OH) solution or hydroxylamine hydrochloride (NH2OH.HCl) solution. The product is washed to become neutral and dried for 4-5 hours at 60-70 degrees C for preparing white powder bacteria cellulose.    USE - Method for preparing white powder bacteria cellulose that is utilized for treating heavy metal ion waste water (claimed).    ADVANTAGE - The bacteria cellulose containing amidoxime group prepared by the method has better stability and quick treatment speed, and satisfies the requirement for treating heavy metal waste water completely. The treatment technique of the heavy metal waste water is achieved by using the bacteria cellulose at low cost. The treatment technique is practicable technically and economically.    DETAILED DESCRIPTION - A method involves cultivating the acetobacter xylinum for 1-2 weeks in a thermostatic incubator to prepare cyanoethyl bacteria cellulose. The bacteria cellulose is dipped in the tetra-alkyl ammonium chloride solution having concentration of 5-10%, and stirred for 15-30 minutes, where mass ratio of bacteria cellulose to tetra-alkyl ammonium chloride is 1:0.2-0.5. Acrylonitrile and alkalis solution having concentration of 30-40% are added to the bacteria cellulose, and reacted for 30-120 minutes at room temperature, where the mass ratio of the alkali solution to bacteria cellulose is 1: 1-2. The reaction liquid is washed with de-ionized water to become neutral after reacting completely. The bacteria cellulose is dried for 5-6 hours at room temperature in a vacuum condition. The prepared cyanoethyl bacteria cellulose is added to 5-15 percent of hydroxylamine (NH2OH) solution or 10-30 percent of hydroxylamine hydrochloride (NH2OH.HCl) solution, where mass ratio of hydroxylamine to the cyanoethyl bacteria cellulose is 5-20:1. pH value is adjusted at 9-10, the bacteria cellulose is reacted for 2-4 hours at 60-90 degrees C. The product is washed to become neutral, and vacuum dried for 4-5 hours at 60-70 degrees C for preparing the white powder bacteria cellulose containing amidoxime group. An INDEPENDENT CLAIM is also included for a method for treating heavy metal ion waste water by bacteria cellulose containing amidoxime group, where heavy metal ion is chosen from copper (Cu2+), lead (Pb2+) and chromium (Cr6+).