Abstract:The counterweight process as an important step in dynamic balancing, will directly affect the quality of dynamic balancing. The relationship between the counterweight and the amount of balance,the amount of unbalance and vibration were researched. The mathematical expression about the balance counterweight was obtained through experimental research and theoretical analysis. Based on the formula,stopping only once,the dynamic balancing without trial weight could be realized. Finally, with the rotor randomly increased the amount of unbalance, by using field balancing technology, this conclusion is verified.