Abstract: The image gray can be changed by severely the speckle noise, so the image resolution can be reduced and the image quality was decreased. In order to control the speckle noise, using a laser at 405nm wavelength as light source of the microscopic imaging system and a voice coil motor vibrating the optical fiber, images was obtained by the polished lens and captured with a CCD image acquisition card, the speckle noise contrasts were studied. The results show that when the fiber vibration amplitude is stable and the vibration frequency is increased from 4Hz to 55Hz, the image speckle contrasts change in the range of 0.0326~0.1197 and the overall trend gradually becomes smaller. The image speckle contrast levels off when the frequency is more than 51Hz. When the speckle contrast reaches the minimum at 0.0326, the image is clear and the laser imaging speckle can be controlled satisfactorily.