Micro-grating accelerometers have the advantages of high precision, low power consumption and small volume. It has wide application prospects in the fields of inertial navigation, oil and gas exploration, and seismic detection. In order to suppress cross-axis interference, a micro-grating accelerometer with double-layer cantilever structure is proposed. The ANSYS finite element analysis shows that the designed double-layer beam structure can effectively suppress cross-axis interference. The modal separation ratio is increased by 13.5 times compared with traditional structures, which effectively improves the resistance to high-order mechanical modal disturbances.