The invention provides a laser focusing spot positioning device which comprises a machine tool at least provided with an X axis, a Y axis, a Z axis and a workbench, a scanning head arranged on the Z axis, a focusing lens arranged below the scanning head, a clamp used for clamping a standard block to be positioned and a sensor. The workbench is arranged on the X axis and the Y axis and moves through the X axis and the Y axis. The clamp and the sensor are both arranged on the workbench. The sensor acquires coordinates of a laser focusing spot formed by focusing of the focusing lens. The invention further provides a laser focusing spot positioning method. The position of the laser focusing spot and the position of a machined area of a workpiece coincide with each other in a non-contact manner, and the problem that in contact type measurement, positioning of the machined workpiece is not accurate is solved so that high-precision machining and positioning can be achieved. The laser focusing spot positioning device is simple in structure and easy to operate to achieve the laser focusing spot positioning method.