In this experiment，the character of forced vibration of a tuning fork is studied，including the displacement amplitude，velocity amplitude and phase difference between driving force and vibration. All the charater can be studied at the same time using Michelson interference method. The result shows that the resonance frequency of displacement amplitude and velocity amplitude are approximately equal; there is a π/2 phase difference between driving force and vibration when the resonance is reached. The change of the phase difference when the driving frequency is increased to the resonance can also be observed.