The invention discloses a device and a method for detecting a multi-core cable, and the device comprises a front wire-connecting terminator, a back wire-connecting terminator, an electroprobe wire-connecting terminator and a plurality of three-level jumper switches. By selecting the connecting states of the three-level jumper switches and cooperating with a multimeter, the invention can implement the detection of the connected state of a multi-core cable which includes the detection of the correct wiring, wrong wiring and connected states, as well as the detection of the short-connected state between centre yarns in the production, installation, debug and inspection process of the equipment of semiconductor technologies and production lines, etc. The invention has simple structure, convenient using and low cost, and can lead the multi-core cable detection to be implemented by a single person, thus saving labor force and improving labor efficiency.