The present invention is provided with a grinding block of dry grinding machine for grinding concrete and granite, the grinding block is assembled to a mill of the grinding machine, the grinding block comprises a fixing plate to fix the grinding block to the mill, wherein the fixing plate is welded with a grinding media, the grinding media comprises a plurality of grinding pieces, the grinding pieces are connected by a connecting strip or connecting strips arranged with space, the connecting strips with spaces divide with a plurality of air passages between two grinding pieces.