The invention relates to the technical field of display by using coherent light as a light source, in particular to a speckle eliminating device based on Mie scatter and perturbation drive, which solves the problems of poor speckle eliminating effect, complicated implementation structure, easiness for damage, high cost, and the like of the traditional speckle eliminating method. The device comprises an optical reflecting cavity and an optical device, wherein an incident light coupling device and a transmission emergent surface are arranged on the optical reflecting cavity; the optical device is arranged opposite to the incident light coupling device of the optical reflecting cavity; the inner walls of the optical reflecting cavity except for the inner wall of the transmission emergent surface are all mirror surface inner walls; the optical reflecting cavity is internally provided with transparent substances filling the whole optical reflecting cavity, and medium particles of which the linearity can cause incident laser to have Mie scattering are dispersed in the transparent substances; and the optical reflecting cavity and the optical device are respectively provided with a perturbation sensitive device, or only one of the optical reflecting cavity and the optical device is provided with a perturbation sensitive device. The device has the advantages of reasonable and compact structure, easiness for realization, low manufacturing cost, good speckle eliminating effect, high laser utilization ratio, stable performance, safety, reliability and light homogenization.