The invention relates to the field of casting machining equipment, in particular to a grinding workbench for cylindrical casting machining. The grinding workbench comprises a table top, support legs,a fixing frame, a telescopic mechanism and an outer grinding roller, the upper surface of the table top is rotatably connected with a rotating table, a rotating cylinder is mounted at the bottom of the rotating table, a rotating shaft is mounted in the rotating cylinder, the top end of the rotating shaft is sleeved with an inner grinding roller, the upper surface of the table top is fixedly connected with a fixing frame, the top of the fixing frame is provided with the telescopic mechanism, the lower end of the telescopic mechanism is fixedly connected with a lifting frame, a two-way lead screw is installed in the lifting frame, the two-way lead screw is sleeved with a sliding block, and the lower surface of the sliding block is fixedly connected with a grinding motor; and a shaft extension end of the grinding motor is fixedly connected with an outer grinding roller, the rotating table drives a casting to rotate, the inner grinding roller grinds the inner wall of the casting, the outergrinding roller grinds the outer side wall of the cylindrical casting, the device can grind the inner side wall and the outer side wall of the cylindrical casting at the same time, and the working efficiency is improved.