The utility model discloses a high-efficiency deep cone sludge thickening device which mainly comprises a deep cone settling tank barrel, an upper oblique cone, a lower oblique cone, a deep cone settling tank cone body, a deep cone settling tank discharge barrel, a deep cone settling tank discharge hole, a deep cone settling tank overflow hole, a deep cone settling tank feeding hole, a deep cone settling tank flocculating agent feeding hole, a static mixer, a stirring device, a deep cone settling tank feeding barrel, and a feeding barrel baffle. The high-efficiency deep cone sludge thickening device effectively overcomes the defects that an activated sludge gravity thickening tank or a gravity thickening pool of a municipal sewage treatment plant is large in occupied land area and low in treating efficiency, thus effectively shortening the settling time and creating conditions for the subsequent deep dehydration of thickened sludge.