The invention discloses a novel sealing piece which comprises a main body component, an O-shaped ring and an auxiliary sealing ring; an O-shaped groove with the cross section being 5.33mm, 3.53mm, 3.1mm or 2.62mm is formed between an outer lip and an inner lip of the main body component; the hardness of the O-shaped ring is 70 plus/minus 5 degrees; the O-shaped ring is installed in the O-shaped groove; and the auxiliary sealing ring is embedded into the main body component and fixes the O-shaped ring. For the novel sealing piece, lips loads due to addition of a system pressure, the system pressure is transferred to the lips through the deformed O-shaped ring to exert the sealing effect, the sealing effect is good, and the wear resistance of the sealing piece is strengthened; and meanwhile,the sealing piece has relatively high anti-extrusion resistance, the maintenance cost of equipment within the shelf life is lowered, the number of times of changing the sealing piece is reduced as for a terminal client, and the working efficiency is improved on the premise of reducing the maintenance cost.