Abstract: A structure of a two-dimensional material-based device having an air-gap and a method for preparing same comprises a substrate, a gate, an dielectric, a two-dimensional material-based film, and source and drain electrodes; the air-gap is formed between the two-dimensional material-based film and the side wall of the dielectric on the gate, or the air-gap is formed between the dielectric and the gate; two-dimensional material-based devices of the above structure utilize the ductility and flexibility of two-dimensional materials to reduce the coupling between the gate and the source/drain electrodes, thereby reducing the parasitic capacitance and the circuit delay; also, the structure ensures that a part of the contact region of the source and drain electrodes with the two-dimensional material can be controlled by the gate, and can thus avoid the reduction in electrical properties and keep a low resistance of the device.