The SMA vibration isolation system of double-flag ring is established, and the method of fast solving the SMA vibration isolation system of doubleflag ring is put forward by the average method and stability analysis. Four kinds of amplitudefrequency curves and their critical loads produced by different load amplitudes are obtained, the appropriate amplitude-frequency curve form for vibration isolation design is selected, and the vibration isolation effect is verified by the transmission rate curve. The results provide a reference for the design of vibration isolation. The relationship between the peak response and the load amplitude is solved, so that the amplitude-frequency curve form can be determined by the load size, and the peak response frequency can be determined to provide a reference for avoiding resonance. The influence of the parameters of the hysteresis curve on the amplitude-frequency curve is studied, and the recommended value range of the parameters of the hysteresis curve is given, which provides a reference for the design and manufacture of SMA.