Using the multiple-scale method, amplitude-frequency response characteristics of a Duffing-van der Pol system were analyzed. Multi-frequency excitation changed the vibration behavior of the Duffing-van der Pol system under single-frequency excitation. Compared with the Duffing system, Duffing-van der Pol system not only makes the curve of the system deviation, but also changes the amplitude of the system. It is shown that the changes of Duffing-van der Pol system amplitude-frequency curve depend on multi-frequency excitation amplitude and frequency. Through the numerical calculations of the Duffing-van der Pol system, it is shown that multi-frequency excitation changes the vibration behavior of the Duffing-van der Pol system under single-frequency excitation; moreover, with the change of the amplitude and frequency of the external excitation, the vibration behavior of the Duffing-van der Pol system has certain change. The conclusions of the experimental are verified with numerical simulations.