The embodiment mode of the invention provides a processing method and a device of a flotation froth image, pertaining to the image processing field. The method comprises the steps that: the image is scanned to obtain the grey-scale value of all the pixels of the image; the grey-scale value of all the pixels of the image is compared with a preset grey scale threshold MIN_GRAY to obtain a high light area; the area of all the high light areas is compared with the preset minimum area threshold, and the area larger than the area threshold is a seed area; a plurality of rays are symmetrically transmitted from the geometric center position of the seed area and the grey-scale value change curve diagrams of the pixels in all the rays are obtained, and the edge of the froth is obtained according to the wave trough positions of the grey-scale value change curve diagrams of all the rays. The embodiment mode of the invention also provides a processing device of the flotation froth image, and the method and the device have the advantages of accurately distinguishing the edge of the froth under the condition of being interrupted by the outside.