For a single degree of freedom damped system with dynamic vibration absorbers (DVAs), a correct mobility matrix of the system on the basis of structure mobility theory is studied in this paper. In addition, analyzed are the expressions of the total power flow input from vibration source to the system, the net power flow transmitted to the main vibration system and the power flow absorbed by DVAs. Furthermore, the control mechanism of DVAs on the transmission characteristics of the power flow is revealed. Finally, an approach to the optimum design of DVAs is proposed in which the power flow is regarded as the control object, and the ordonnance relations among optimum parameters of DVAs dealt with. For a single degree of freedom damped system with dynamic vibration absorbers (DVAs), a correct mobility matrix of the system on the basis of structure mobility theory is studied in this paper. In addition, analyzed are the expressions of the total power flow input from vibration source to the system, the net power flow transmitted to the main vibration system and the power flow absorbed by DVAs. Finally, an approach to the power flow is revealed. of DVAs is proposed in which the power flow is regarded as the control object, and the ordonnance relations of optimum parameters of DVAs dealt with.