The invention discloses a multi-stage conical synchronous expansion anchor rod which consists of a rod body, a screw nut, a tray, a tray gasket, a casing pipe gasket and a casing pipe, wherein the rod body consists of a plurality or taper bodies; an anchor head is arranged at the tail part of the rod body; the anchor head is a column body; a through grouting tube is arranged in the center of the rod body; discharge holes are formed inside the anchor head; the discharge holes are communicated with the grouting tube. The casing pipe is externally shaped as a column, the inner shape of the casing pipe is matched with the taper body of the rod body, and the casing pipe is provided with two through casing pipe slots which divide the casing pipe into two parts.