Disclosed is a reverse flow multi-stage sedimentation rake-free thickening device relating to the field of slime water treatment. The device includes a feed assembly, a guide assembly, and a clean coal collection assembly. The guide assembly also includes a central tank body and coal slurry flows from the upper part of the central tank body to the inner side wall of the central tank body through the feed assembly and the medicament, and then flows to the middle of the central tank body through the guide assembly. After the reaction, the bubbles carry the fine coal slime and move up to the clean coal collection assembly. The clean coal collection assembly is located above the outlet of the guide assembly, and the clean coal collection assembly is sequentially provided with a central collection area, a defoaming area, and a diversion settlement area from the middle to the outside.