The invention relates to a totally closed oil bath type reciprocating motion supporting device for a cement clinker grate cooler. The totally closed oil bath type reciprocating motion supporting device is characterized by comprising two right-angle supporting bent plates, a main hanging beam, connection blocks, bearing guide rail beams, a guide block, a guide shaft, a shaft sleeve, bearings, a lubricating oil box and a sealing cover, wherein the two right-angle supporting bent plates are oppositely fixed at the bottom of a strip-shaped shuttle-type grate plate unit along the longitudinal direction of the shuttle-type grate plate unit, and the main hanging beam is arranged between the two right-angle supporting bent plates and connected with supporting pillars; the bottom of the main hanging beam is connected with the guide block through the connection blocks; a shaft hole is formed in the center of the guide block; transverse supporting shafts are arranged on two sides of the shaft hole; the bearings are sleeved at the ends of the supporting shafts; the bearing guide rail beams are arranged on the top parts of the bearings; the guide shaft passes through the shaft hole, and is fixed on the right-angle supporting bent plates; the lubricating oil box accommodates the bearing guide rail beams, the guide block, the guide shaft, the shaft sleeve, the bearings, the connection blocks and the two right-angle supporting bent plates, and the lower part of the lubricating oil box is fixed on the right-angle supporting bent plates; and the sealing cover is covered on the top of the lubricating oil box. The totally closed oil bath type reciprocating motion supporting device has the advantages that the abrasion to machine parts is reduced to the lowest extent, the energy is saved, and the cost is reduced.