A new method for measuring the vibration frequency of a vibrating object was put forward. The experiment system was put up and a lot of experiments were made. The system can give out the vibration model of a vibrating object by receiving the scattered light of the vibrating object and then making an auto-correlation of the scattered light. Moreover, the system gives out the vibration frequency spectrum by doing a Fast Fourier Transform (FFT) to the auto-correlation data. Adopting optic-fiber to transmit the scattered light, adopting a photomultiplier as a photon detector and adopting a data processing technique combined FFT with auto-correlation analysis, the system can work well without any special request both to the light source and the measured object. Furthermore, the system has a wide range of application, being simple to operate, and is easy to be used in non-contacting, long-distance and network way. The simulated experiments indicate that the system works well in a wide frequency range of 1 Hz to 10⁵ Hz.