Abstract: Laser speckle has important applications in many areas, such as optical coherence tomography, holography, multimode optical fiber communication and metrology. In order to evaluate the laser speckle, the power spectrum width of speckle image in frequency domain was proposed as the evaluation method of laser speckle. The experiment device of power spectrum speckle evaluation was designed based on optical fiber vibration. A 0.5W, 532nm laser was used as light source and a voltage-driven voice coil motor was used to vibrate the fiber and control laser speckle. A CCD image acquisition card was used to collect images. Speckle contrast method and power spectrum method were respectively used to evaluate the speckle images under different driving voltages. The results show that the method of power spectrum has higher sensitivity and wider range of evaluation.