Abstract: In order to reduce the pollution of soluble sericin in waste water of silk industry,condensed the waste water which had been processed by acid using the separating technics of hollow fiber membrance,and then dried the concentrated solution of the sericin by drying technics of sentrifugalizing and spraying to obtain pure sericin protein.There is a large number of sericin protein in waste water. After the waste water is processed by the way described above,its COD_Cr can be reduced to about 80 mg/L and meet the need of draining standard or achieve the level of water used in making silk so that the water can recycle.And by this means sericin protein in waste water can be efficiently recycled and new by\|products of sericin protein were developed.