Abstract: A surface-mounted transformer includes an adhesive layer and a winding product. The winding product is disposed inside the adhesive layer; the winding product includes an I-shaped magnetic core and a coil wound on a middle pillar of the I-shaped magnetic core; leading-out ends of the coil are connected to electrodes; the electrodes are exposed on the surface of the adhesive layer; and the adhesive layer is obtained through compression molding forming of a magnetic molding material. Compared with a surface-mounted transformer in the prior art, which has equal performance indexes, the surface-mounted transformer has a smaller size with a decrease proportion of over 50%; and a BOBBIN and an insulating rubber tape do not need to be used in processing. The winding product in the surface-mounted transformer is completely covered by the adhesive layer, so that the product is high in reliability and can support a PSIP plastic package environment.