The invention relates to a fixing device of a vertical disc filtering machine distribution head sealing ring. The fixing device comprises a fixing plate, wherein the fixing plate is provided with a fixing opening; a regulating device is arranged on the fixing plate, and comprises a fixing ring, a regulating ring, three regulating rods and a folding telescopic pipe; the fixing ring is fixedly connected with the fixing plate and is coincident with the circle center of the fixing opening; one end of each of the three regulating rods is connected with the fixing ring; the other end of each of thethree regulating rods is connected with the regulating ring; the two ends of the folding telescopic pipe are respectively and fixedly connected with the fixing ring and the regulating ring; a placingtable is respectively arranged on the top and one side of the regulating ring; the placing table is used for installing a laser horizontal instrument; a scale bar parallel to a main shaft of a vertical disc filtering machine is correspondingly arranged on a main shaft of the vertical disc filtering machine. The fixing device has the advantage that by regulating the three-dimensional direction of the sealing ring, the distribution head leakage condition caused by the abrasion of the main shaft and the sealing ring due to the non-vertical state of the main shaft and the sealing ring of the vertical disc filtering machine can be avoided.