The invention discloses a clamping device for machining of a disc brake support. The clamping device for machining of the disc brake support comprises a bridge board, wherein components arranged on the two side faces of the bridge board are distributed in a central symmetry mode with the bridge board as the symmetry plane, and the components on one side face of the bridge board are distributed in a mirror symmetry mode; middle boards are vertically installed on the bridge board; the two ends of each middle board are respectively provided with a cavity for containing one pressing board; the pressing boards are driven by transverse pull oil cylinders to move in the direction perpendicular to the middle boards; locating oil cylinders are installed on the mirror symmetry line of the bridge board; the locating oil cylinders and the transverse pull oil cylinders are located on the same sides of the middle boards; each locating oil cylinder drives a stand column parallel with the corresponding middle board to move towards or away from the middle board; the positions, at the two ends of each middle board, of the bridge board are respectively provided with a turning oil cylinder; each turning oil cylinder drives a clamping board parallel with the bridge board to move towards or away from the bridge board. The clamping device can carry out multi-procedure and multi-space-angle shape and position surface machining through one time of clamping, efficiency is high, cost is lowered, and the uniformity of disc brake supports is good.