In this paper, based on the actual need of production, a new technic method-ZS method on duple fact dynamic balance of machine rigid rotators is presented for small-scale production. The unbalanced weight and direction are obtained by adding duple test weight and measuring the bearing amplitude to the rotator system. The primary principle is developed in detail and the rightness of the new method is proved out by the simulant test and the applied real example. The outstanding advantage of the new method is that the investment cost is low and the adaptability is strong. There is a spacial application value for the great dajority of the mid and small enterprises that produce rotators in small-scale but usually the rotator standards need to be changed.