The invention discloses a high-ash fine-particle coal slime sorting device and method which are applicable to the field of coal slime flotation devices. A foam sprinkling device arranged in the top end of a columnar structure; a fine coal discharge opening is formed in the bottom of a fine coal overflow tank; a feeding pipe is axially arranged in the circle center of the columnar structure; the feeding pipe is provided with a feeding device; two groups of filling devices are respectively strung on the feeding pipe; the filling devices adopt closely arranged cylindrical structures; the cylindrical structures are longitudinally penetrated; an internal sprinkling water washing device matched with the body of a flotation column is arranged inside the cylindrical structure and is close to the inner wall of the cylindrical structure; a middling discharge device is arranged below the cylindrical structure; a scavenging section is arrange at the bottom of the middling discharge device; a circulating pump and a micro-bubble generator are sequentially connected with an external outlet through pipelines; a plurality of hydrocyclones are separately arranged above the side wall of the fine coaloverflow tank; each hydrocyclone is provided with a material inlet connector; the material inlet connector is connected with a middling discharge opening. The device is compact in structure, and caneffectively enhance the recovery rate and fine coal quality of high-ash difficult floatable coal slime flotation products, and reduce coarse particle loss in coal particles.