The invention discloses a method and a device for arranging and positioning an electrocardio-electrode. The positioning method comprises the following steps of: 1, determining an upper breastbone edge and a lower breastbone edge and placing, sticking or marking markers, which are called an upper breastbone edge marker and a lower breastbone edge marker, at the two positions respectively, wherein the two markers are used as a first reference point and a second reference point; 2, determining a third reference point; and 3, determining the arranging position of a measuring electrode in front of a breast according to the first, second and third reference points. The positioning device comprises a positioning device using a distance measuring method, a positioning device using a reference position projecting method, a positioning device applying a light spot projecting method and a video image matching method-based positioning device.