A machining method for machine tools, characterized by: displaying a drawing file on a monitor of a machine tool; setting an origin point of the drawing file to match an origin point of a work piece with a tolerance; setting a plurality of reference points of the drawing file to match a corresponding plurality of reference points of the workpiece within the tolerance; selecting a processing file which includes a plurality of processing coordinates stored in the processing file; initially checking if the origin points of the drawing file and of the work piece are matched within the tolerance; moving the work piece so that each of the workpiece reference points is shifted to a corresponding one of the plurality of processing coordinates, wherein a shift of the work piece is detected by the machine tool and a shift direction thereof is displayed on the monitor so that a given workpiece reference point and the corresponding processing coordinate are overlapped and matched within the tolerance to inhibit misjudging or reading incorrect coordinate values; performing the machining operation, wherein a processing switch is pressed to transmit an activating signal to a system processor of the machine tool to initiate a processing step; executing a first checking step by checking if the work piece location is matched, within the tolerance, at a corresponding position of one of the processing coordinates: if not, showing an error message on the monitor, not performing the processing, and the moving step must be finished by an operator; if yes, proceeding; executing the processing step of the work piece by the machine tool; executing a second checking step by checking if the machine tool finishes the processing of the workpiece at the corresponding processing coordinate; if not, continue the processing step; if yes, proceeding; executing a stop step of stopping the processing of the machine tool; executing a third checking step by checking if all processing coordinates of the processing file and the corresponding all reference points of the work piece are completed processing; if not, return to the moving step; if yes, proceeding; and displaying a completed status when operations on all reference points of the workpiece are completed. displaying a drawing file on a monitor of a machine tool; setting an origin point of the drawing file to match an origin point of a work piece with a tolerance; setting a plurality of reference points of the drawing file to match a corresponding plurality of reference points of the workpiece within the tolerance; selecting a processing file which includes a plurality of processing coordinates stored in the processing file; initially checking if the origin points of the drawing file and of the work piece are matched within the tolerance; moving the work piece so that each of the workpiece reference points is shifted to a corresponding one of the plurality of processing coordinates, wherein a shift of the work piece is detected by the machine tool and a shift direction thereof is displayed on the monitor so that a given workpiece reference point and the corresponding processing coordinate are overlapped and matched within the tolerance to inhibit misjudging or reading incorrect coordinate values; performing the machining operation, wherein a processing switch is pressed to transmit an activating signal to a system processor of the machine tool to initiate a processing step; executing a first checking step by checking if the work piece location is matched, within the tolerance, at a corresponding position of one of the processing coordinates: if not, showing an error message on the monitor, not performing the processing, and the moving step must be finished by an operator; if yes, proceeding; executing the processing step of the work piece by the machine tool; executing a second checking step by checking if the machine tool finishes the processing of the workpiece at the corresponding processing coordinate; if not, continue the processing step; if yes, proceeding; executing a stop step of stopping the processing of the machine tool; executing a third checking step by checking if all processing coordinates of the processing file and the corresponding all reference points of the work piece are completed processing; if not, return to the moving step; if yes, proceeding; and displaying a completed status when operations on all reference points of the workpiece are completed.