The invention provides a device unit body containing metal, polyimide and a blocking layer structure and a fabrication method of the device unit body. The device unit body comprises a substrate, an insulation oxide layer, a first metal layer, a first silicon dioxide layer, a first silicon nitride layer, polyimide, a second metal layer, a second silicon dioxide layer and a second silicon nitride layer and is characterized in that the first metal layer and the polyimide are sequentially separated by the first silicon dioxide layer and the first silicon nitride layer, and the second metal layer and the polyimide are sequentially separated by the second silicon dioxide layer and the second silicon nitride layer. The device unit body is applied to an on-chip spiral transformer, copper is taken as an induction coil, and the polyimide is taken as an intercoil medium; and with the adoption of the blocking layer structure between the metal copper and the polyimide, the copper can be effectively prevented from being diffused to the polyimide, the pressure resistance of the device is improved, and the performance of the device is improved.