The invention discloses a speed changer lubrication structure which comprises a lubricating oil track located between a transmission shaft of a speed changer and a rear cover. The lubricating oil track is provided with a rotation axis, a plurality of locking bosses I are evenly distributed on the lubricating oil track along the concentric circle direction of the rotation axis, a plurality of locking bosses II matched with the locking bosses I are arranged on the rear cover, the locking bosses I and the locking bosses II all comprise first arc surfaces which are identical in shape, the center of circle of each arc surface is not located on the rotation axis. According to the structure, a user just needs to rotate the lubricating oil track to enable the first arc surfaces of the locking bosses I and the first arc surfaces of the locking bosses II to be pressed or separated, and therefore the lubricating oil track can be fixed or can move on the axis direction relative to the rear cover, structure is simple, operation is convenient, internal space of the speed changer is not occupied much, the structure of a shell of an existing speed changer does not need to be changed, and cost is saved.