The invention relates to a sliding bearing sealing structure of a spiral main shaft of a horizontal screw centrifugal machine. A bearing sleeve, a sealing ring, a large end support and a hollow shaftare included. The sliding bearing sealing structure of the spiral main shaft of the horizontal screw centrifugal machine is characterized in that with the center line of the total length of the bearing sleeve as reference, a left-handed rotation spiral groove and a right-handed rotation spiral groove are oppositely formed in the hole wall of an inner hole of the bearing sleeve; the rotation direction of the left-handed rotation spiral groove close to the sealing ring is the same as the rotating direction of the hollow shaft; the rotation direction of the right-handed rotation spiral groove away from the sealing ring is opposite from the rotating direction of the hollow shaft; and the bearing sleeve is provided with a plurality of oil injecting holes communicated with the left-handed rotation spiral groove and the right-handed rotation spiral groove. The sliding bearing sealing structure of the spiral main shaft of the horizontal screw centrifugal machine has the beneficial effects thatcompared with the prior art, the left-handed rotation spiral groove, the right-handed rotation spiral groove and a labyrinth seal form the overall lubricating grease sealing structure, lubricating grease in the bearing sleeve is effectively sealed and stored, the function of storing the lubricating grease for relatively long time is achieved, the function time of the lubricating grease is prolonged, the lubricating grease adding frequency is reduced, the shutdown overhauling time is saved, and the production efficiency of the machine is greatly improved.