The invention relates to a wire icing experimental device under the natural state and belongs to the technical field of wire experimental devices. Four wheels and a magnetic field sensor are mounted at the bottom of a vehicle body of the wire icing experimental device; a water tank, a storage battery groove and a control box are arranged at the upper part of the vehicle body; a water pump is mounted at the upper part of the water tank; an upper arm is directly mounted on the vehicle body and is hinged to a lower arm; an atomizer is mounted at the top end of the upper arm and is hinged to an upper arm bracket. A storage battery provides electric energy for the whole system; the water pump pressurizes water and enables water to be ejected out of the atomizer. According to different sags of wires subjected to an experiment, an included angle between the upper arm and the lower arm as well as between the atomizer and the upper arm can be properly adjusted, and the atomizing direction and the atomizing height can be controlled. The wire icing experimental device assists icing of the wire subjected to the experiment in a water mist spraying manner, promotes the icing efficiency, improves the icing quality, is simple in structure, high in reliability, can be adapted to more hostile environments, and can effectively ensure safety of workers when replacing manual icing.