The invention discloses a sewage precipitate separating device. The sewage precipitate separating device comprises a supporting frame and is characterized in that a precipitation pool is arranged on the supporting frame; an extrusion plate is arranged in the precipitation pool; one side of the precipitation pool is connected with a sewage input end; a sewage output end is arranged on the other side of the precipitation pool; the sewage precipitate separating device is arranged in the precipitation pool; an overturn baffle plate is arranged on the lower surface of the precipitation pool; a sewage backflow device is arranged below the precipitation pool; a control panel is arranged on the outer wall of the precipitation pool. When domestic sewage, crop water and the like are filtered, the sewage needs to be precipitated and can be filtered well, and sewage impurities fall onto the bottom of the pool after being precipitated; when the precipitated sewage is discharged, flowing of the precipitate at the bottom caused by sewage discharge is avoided, so the sewage precipitate separating device has good precipitation effect and high efficiency, and is simple in structure and convenient touse.