For the vibration noise problem of strap-down inertial navigation system in the vehicle, a better vibration damping system was designed. Based on the vibration characters of the vehicle environment, a vibration damping model fitted the SINS in the vehicle was presented; and then the mechanism of vibration damping system was designed especially; and then the design of vibration damping system was verified by using of the dynamic characteristic analysis, On the basis of the above analysis, the overall structure of actual vibration isolation system was built, and then the test for the vibration isolation system was made, the results show that the micro-isolation system for the SINS system vibration and noise has a better inhibition effect, and the applicability and the dependability of the vibration damping system is verified by the test results, which provides reference basis for the design of the strap-down inertial navigation damping system in the land vehicle and provides techniques for the better application of SINS in other fields.