This paper studies in detail the factors leading to the surge and the preventative surge control theory of the type of D200-0.28/0.97 high pressure centrifugal air-blower from the experience of installing, testing and using it in the nonferrous metal industries, a simple and reliable preventative surge control method is presented. The preventative surge control point is calculated in the centrifugal air-blower and the operation specification of preventative control surge is put forward.