The invention provides an electromagnetic chemical sensor based on a conductive polymer and a preparation method thereof. The preparation method comprises the following steps: mixing an oxidizing agent containing a trivalent iron ion or peroxydisulfate with cationic polyelectrolyte, so that an oxidizing agent/high-molecular polymer mixed solution is obtained; preparing the oxidizing agent/high-molecular polymer mixed solution into an oxidizing agent/high-molecular polymer coil structure; carrying out heat treatment on the oxidizing agent/high-molecular polymer coil structure, so that an oxidizing agent/high-molecular polymer coil structure with self supporting effect is obtained; putting the oxidizing agent/high-molecular polymer coil into monomer atmosphere, and carrying out polymerization, so that a conductive polymer/high-molecular polymer coil structure is obtained; and preparing electrodes at the two ends of the conductive polymer/high-molecular polymer coil structure, so that theelectromagnetic chemical sensor based on the conductive polymer is obtained. The electromagnetic chemical sensor based on the conductive polymer realizes an effect that the conductive polymer is welldispersed in a composite material, so that the composite material can be used as a sensitive unit of an electromagnetic sensor.