The invention provides a cuttable flexible wire, which is composed of liquid metal and elastic body, and liquid metal particles are dispersed in the elastic body. After the flexible wire is cut, the liquid metal material will not flow out, and it can withstand deformations such as stretching and bending. When deformations such as stretching and bending occur, its resistance will basically not change. The present invention also provides a device capable of preparing a large-scale cuttable flexible wire, including a material mixing device, a current detection device, a conductor pipeline, a protective layer pipeline, and a heating device, and the performance of the cuttable flexible wire prepared by the device is Stable, large tensile strain, recoverable after stretching, and the wire can be cut, which has potential application value in flexible electronics.