Concerning the problem that the flexible gyro SIMU is sensitive to vibration and its dynamic precision is low in vibration, the paper analyzed the adaptability of the flexible gyro SIMU and studied the navigation accuracy in various vibration conditions. It showed that the additional drift generated in vibration is the main cause of low vibration adaptability of the flexible gyro SIMU. The result of vibration navigation test showed the flexible gyro SIMU will be in good agreement between the ground experiment en-vironment and the flight environment when the flying missile's vibration is decreased to 1g or so. The method of improving the a-daptability under vibration environment is also presented.