The invention relates to a device for treating tail water produced by waste recycling; the device comprises a waste water conveying device, a flotage-sludge separation device, a mechanical grid and a vertical flow sedimentation tank, wherein a water outlet end of the waste water conveying device is communicated with a water inlet end of the flotage-sludge separation device, a water outlet end of the flotage-sludge separation device is communicated with a water inlet end of the mechanical grid, and a water outlet end of the mechanical grid is communicated with a water inlet end of the vertical flow sedimentation tank. By adopting the technical scheme of the invention, the flotage-sludge separation device is used for carrying out first stage of separation on sludge, so that the sludge with larger particle sizes can be separated; the mechanical grid is used for carrying out first stage of separation on larger flotage; the vertical flow sedimentation tank is used for carrying out second stage of separation on the sludge and the flotage; therefore, the device is capable of carrying out two-stage separation on the sludge and the flotage, thus more thoroughly and efficiently separating the sludge and the flotage in waste water; the device for treating the tail water produced by waste recycling has a characteristic of being simple in structure; the sludge separated by the device can be directly used in building materials, so that environment-friendly utilization is realized.