The invention discloses an antimony/carbon nano-fiber flexible material, a preparation method thereof and an application. The method includes the steps: synthesizing antimony-containing nano-particles by a precipitation method; dissolving polyacrylonitrile into N, N-dimethyl formamide; adding a certain amount of nano-particles to uniformly mix to form electrostatic spinning fluid; spinning the spinning fluid into nano-fibers in a static electricity manner; pre-oxidizing the nano-fibers, and calcining the pre-oxidized nano-fibers in argon atmosphere at the high temperature to obtain antimony/carbon nano-fibers. The method is simple and easy to control, the synthesized nano-fibers are uniform in size and high in physical strength, carbon materials can effectively wrap antimony materials, and the carbon nano-fibers have good electrochemical performance without binding agents and conductive agents and excellent application prospect.