Disclosed is a magnetic excitation coil structure including a magnetic coil sheet formed of a thin film and rolled as a cylindrical body with a hollow hole, and an insulation layer covering the outer surface of the cylindrical body formed by the magnetic coil sheet for protection. The magnetic coil sheet includes a flexible substrate, a dielectric layer attached to the flexible substrate, and a plurality of patterned circuit layers embedded in the flexible substrate and in contact with the dielectric layer. Each patterned circuit layer is separate, and the upper surfaces of the patterned circuit layers and the upper surface of the flexible substrate form a co-plane. The magnetic coil structure provides an electrical function of coil, which is enhanced by the patterned circuit layer due to its high aspect ratio of the electrical circuit, thereby greatly increasing the whole magnetic flux and electromagnetic effect.