The invention discloses a preparation method of miniature conductive fiber, belonging to the conductive fiber material field. The miniature metal particles, with protection argon which is high-speed flowing, flow into a sediment chamber. Two metal electrodes are arranged in the sediment chamber. The metal electrodes are provided with HVDC, so an electrostatic field is formed between the two metalelectrodes. During the metal particles sediment, the particles interact to form miniature metal particle chain because of the electrostatic field. The sediment chamber is positioned in a high temperature furnace with the protection of protection gas. The miniature metal particle chains are sintered for two hours at 900 to 930 centigrade. Then the miniature metal particle chains convert into miniature metal particle fiber. The average length of the fiber is 3005 micrometer and the average diameter is 5 micrometer. The method has the advantages that: the craft is simple; the cost of equipments is low; the invention is an important application in the preparation field of miniature conductive fiber.