Abstract: Based on the electromechanical similarity theory and the characteristics of the inerter， which is similar to the capacitor in the characteristics that high frequency can pass but low frequency cannot， a single wheel vehicle model of two-stage ISD suspension with "inerter-spring-damper"(ISD)in each level was established. The influence of the inertia coefficient of vehicle suspension on the transmission characteristics of the two-stage ISD suspension system was simulated and analyzed， and the dynamic response of the vehicle suspension system under random and pulse input was discussed in the frequency domain and the time domain respectively. The results showed that under the requirement of the acceleration gain of the vehicle body， the proper improvement of the inertia coefficient can improve the vibration damping performance of the two-stage ISD suspension system. The two-stage ISD suspension has a better low-frequency vibration damping performance than the classic ISD suspension.Compared with the traditional passive suspension， the two-stage ISD suspension has a better comprehensive vibration damping performance.

Key words: inerter, vehicle suspension, vibration performance, two-stage vibration reduction, transmission characteristics