The invention discloses a bearing lubricating system for a disc separator. The bearing lubricating system comprises a machine base, a vertical shaft system fixed to the machine base and a foundation. The vertical shaft system comprises a vertical shaft, an upper bearing and a lower bearing. The machine base is provided with a machine base cavity. The vertical shaft penetrates a cavity body of an oil cavity of the machine base. The upper end of the vertical shaft is connected with the upper end of the machine base through the upper bearing. The lower end of the vertical shaft is connected with the lower end of the machine base through the lower bearing. The vertical shaft is provided with a center oil hole in the axial direction. The portions, close to the upper bearing and the lower bearing, of the vertical shaft are provided with side oil holes in the radial direction. A lower bearing lubricating oil way is formed by a gap among the oil cavity of the machine base, the lower bearing, the machine base and the foundation. An upper bearing lubricating oil way is formed by a vertical stand center hole, the side oil holes, the upper bearing and the oil cavity of the machine base. The bearing lubricating system can control the amount of lubricating oil at the bottom bearing and can adjust the amount of lubricating oil at the top bearing, so that the problem that lubricating is insufficient due to the fact that multiple bearings are connected in series or the distance between an upper bearing and a lower bearing is longer is solved effectively, and the reliability of gears and the bearings is guaranteed.