The invention relates to a wire cable unit length direct-current resistance measuring device and method, and relates to the technical field of wire cable detection. The measuring device is mainly composed of a device structure unit and a measuring module unit, wherein the device structure unit comprises a to-be-tested wire cable, a first copper-made buckle, a first copper-made connecting wire, a resistor, a second copper-made connecting wire, an electronic switch and the like; the measuring module unit comprises a temperature measuring module, a signal amplifying module, an A/D conversion module, a single chip microcomputer and a liquid crystal display module which are electrically connected in sequence, wherein the single chip microcomputer receives a control signal input by a human-computer interaction module, and controls the action of the electronic switch. The adopted cable length measuring method is simple and easy to perform, does not damage the cable, and can perfectly replacea current cable length detection method with damage and low work efficiency. By achieving the purpose of measuring the wire cable length, the measurement of wire cable unit length direct-current resistance is simpler and faster.