Provided are a grouting anchor bolt and a grouting anchor cable for supporting of large deformation and constant resistance and a quantitative roadway supporting method, wherein an anchor bolt comprises a casing, a hollow rod body, an anchor cylinder, a tray, a fastening nut and a clamping pin, a front end of the casing is sealed and a rear end of the casing is opened, a middle position of the casing is provided with a plurality of grouting holes, an inner diameter of the casing from the middle position of the casing to the rear end becomes small gradually, a side surface of a front end of the hollow rod body is sleeved with an anchor cylinder, the anchor cylinder is inserted into the casing and movably connected with the casing, the anchor cylinder is connected with the casing through the clamping pin, a rear end of the hollow rod body is sequentially assembled and connected with the tray and the fastening nut. The beneficial effects herein are as follows: the anchor bolt and the anchor cable simple in structure, easy to process, simplifies operations of supporting and grouting, and therefore particularly suitable for supporting of large deformation for surrounding rocks. The self-bearing capability of surrounding rocks is improved, and the supporting of large deformation of surrounding rocks is provided through constant resistance, thereby realizing organic combination of “yielding-supporting” and “active-passive supporting”; the quantitative roadway supporting method may realize quantitative supporting for a roadway.