The invention discloses a full-automatic silicon steel sheet measuring device. The measuring device comprises an inclined working table, an automatic walking device, a visual identification and tracking device, a computer control system; a grating measuring scale is arranged on the automatic walking device, the computer control system comprises an industrial grade image processing computer, an initialization module, an information acquisition module, an information processing module, a visual control module and an information display module. The method for automatically measuring a silicon steel sheet comprises the following step: initial data required by the current measurement are set through the initialization module; a starting button is clicked, and the current measurement is in a hole-free measurement mode or a hole measurement mode is judged; and the silicon steel sheet is automatically measured, a skeleton diagram of a measured workpiece is drawn and a measurement result is displayed. Automatic measurement can be achieved according to the hole and hole-free mode and the length of the silicon steel sheet, automatic comparison with a silicon steel sheet data table can be realized, sound-light alarm can be sent out when an error exists, and the measuring efficiency can be improved.