A method of making sound-absorbing micro-holes on a metal plate, comprising the steps of:. feeding a metal plate on a workbench forward to extend beyond a shearing edge of the workbench, such that a first surface disposed at a bottom of the metal plate is contacted with the workbench, and a part of the metal plate is protruded and extended beyond the shearing edge of the workbench;. locating a punching head at a first position at a top of the shearing edge of the workbench, and maintaining a working space between the punching head and the workbench, wherein the punching head includes a plurality of unit blade portions arranged in a row parallel to the shearing edge of the workbench;. applying a shearing force to the workbench by the punching head;. applying a force to bend the metal plate along the direction of applying force by the punching head, and forming a plurality of spot-shaped cavities arranged in a row on a second surface of the metal plate by an action of the unit blade portions towards the workbench;. bearing the shearing force on the first surface of the metal plate to form a linear groove along the shearing edge of the workbench;. deforming the metal plate by the shearing force, interconnecting the spot-shaped cavities arranged in a row on the second surface with the linear groove on the first surface, and forming a plurality of micro-holes at the intersection of the interconnection;. returning the punching head to the first position, and then shifting the punching head to a working distance in a direction parallel to the shearing edge to a second position;. feeding the metal plate in a direction towards the shearing edge of the workbench again;. repeating Steps C, D, E and F when the punching head is situated at the second position; and. returning the punching head to the second position, and then shifting the punching head to a working distance in a direction parallel to the shearing edge of the workbench and returning the punching head to the first position to complete a processing cycle., wherein the number of unit blade in Step B and the feed stroke of the metal plate in Step H are controlled, such that the number of the micro-holes formed on the metal plate ranges from 80000 to 450000 per square meter, and the metal plate has a hardness HRB ranging from 8 to 40 and a ductility ranging from 4 to 30, and wherein the Step F further comprises a Step F1 to control a stroke of the punching head, such that the micro-holes, formed after the spot-shaped cavities arranged in a row on the second surface of the metal plate and the linear groove on the first surface of the metal plate are interconnected, have a minimum width in the horizontal direction smaller than a thickness of the metal plate.. feeding a metal plate on a workbench forward to extend beyond a shearing edge of the workbench, such that a first surface disposed at a bottom of the metal plate is contacted with the workbench, and a part of the metal plate is protruded and extended beyond the shearing edge of the workbench;. locating a punching head at a first position at a top of the shearing edge of the workbench, and maintaining a working space between the punching head and the workbench, wherein the punching head includes a plurality of unit blade portions arranged in a row parallel to the shearing edge of the workbench;. applying a shearing force to the workbench by the punching head;. applying a force to bend the metal plate along the direction of applying force by the punching head, and forming a plurality of spot-shaped cavities arranged in a row on a second surface of the metal plate by an action of the unit blade portions towards the workbench;. bearing the shearing force on the first surface of the metal plate to form a linear groove along the shearing edge of the workbench;. deforming the metal plate by the shearing force, interconnecting the spot-shaped cavities arranged in a row on the second surface with the linear groove on the first surface, and forming a plurality of micro-holes at the intersection of the interconnection;. returning the punching head to the first position, and then shifting the punching head to a working distance in a direction parallel to the shearing edge to a second position;. feeding the metal plate in a direction towards the shearing edge of the workbench again;. repeating Steps C, D, E and F when the punching head is situated at the second position; and. returning the punching head to the second position, and then shifting the punching head to a working distance in a direction parallel to the shearing edge of the workbench and returning the punching head to the first position to complete a processing cycle., wherein the number of unit blade in Step B and the feed stroke of the metal plate in Step H are controlled, such that the number of the micro-holes formed on the metal plate ranges from 80000 to 450000 per square meter, and the metal plate has a hardness HRB ranging from 8 to 40 and a ductility ranging from 4 to 30, and wherein the Step F further comprises a Step F1 to control a stroke of the punching head, such that the micro-holes, formed after the spot-shaped cavities arranged in a row on the second surface of the metal plate and the linear groove on the first surface of the metal plate are interconnected, have a minimum width in the horizontal direction smaller than a thickness of the metal plate.