Line spectra are the most visible signs of the submarines’ radiated noise spectrum since they may be detected even at low speeds, when submarines produce minimal noise. The potential of chaotifying vibration isolation systems to reduce line spectra of underwater vehicle and improve its capability of concealment have recently reported. Notice that for an isolation system, the amplitude of chaotifying vibration is, in general, larger than that of its specified periodic motion subject to the inherent characteristic of chaotic behavior. A new method based on the sliding mode control was advanced to realize the projective synchronization between the two-degree-of-freedom vibration isolation system and the chaotic system based on sliding mode control .The presented method can effectively eliminate the linear spectra based on chaotifiy vibration responses and the capability of vibration isolation. The effectiveness of the proposed scheme was validated by the numerical simulation .The simulation results show that linear spectra is reduced and the vibration amplitudes of isolated equipment is proportionally diminish, moreover, This method need not calculate Lyapunov exponent and the proposed controller takes on strong robustness for parameter uncertainty and influence of measurement noise.