An EMI shielding device is provided. A first shielding layer is formed on a first surface of a first substrate, and a first through hole is formed through the first substrate. A second substrate is mounted in an opening of the first through hole, and a second shielding layer is formed on a surface of the second substrate. A conductive paste is mounted between the first substrate and the at least one second substrate to electrically connected the first shielding layer and the second shielding layer. The EMI shielding device is adopted to be mounted on a printed circuit board (PCB) by Surface Mount Technology. Therefore, the EMI shielding device may be firmly mounted on the PCB, and there is not any narrow gap that may leak electromagnetic radiation.