An apparatus (2) for automatically laying out punching tools on a turret is used in a computer-aided manufacturing system for sheet-metal punching. The system includes a server (1), a database (3), and a number of client computers (7). The apparatus resides in the server, and is used for receiving drawings from the client computers to obtain information on workpieces, selecting punching tools in accordance with sizes and shape of each type of drawing entity of the workpieces and in accordance with materials of the workpieces and machining allowances set by users, selecting a corresponding tool station on the turret for each of the selected punching tools in accordance with a type of the turret and specifications of the selected punching tool, mounting each punching tool on the corresponding tool station, selecting an optimum manufacturing path for each punching tool, and recording punching tool layout information. A related method is also disclosed.