A method for fabricating an MEMS microphone, comprising: Step 1, providing a diaphragm silicon substrate, and a multi-cavity silicon backplate with a center area and a boundary area surrounding the center area, a plurality of holes being arranged in the multi-cavity silicon backplate; Step 2, depositing a first dielectric layer on both upper and lower surfaces of the multi-cavity silicon backplate, the first dielectric layer covering bottoms and sidewalls of holes, and depositing a second dielectric layer on both upper and lower surfaces of the diaphragm silicon substrate; Step 3, bonding the lower surface of the diaphragm silicon substrate to the upper surface of the multi-cavity silicon backplate to form capacitor plates of the MEMS microphone; Step 4, thinning the diaphragm silicon substrate to form a monocrystalline silicon diaphragm of the MEMS microphone; Step 5, partially etching the monocrystalline silicon diaphragm and stopping the etch at the second dielectric layer to form a groove and a plurality of spring structure slots in the boundary areas, the spring structure slots and the monocrystalline silicon diaphragm near the spring structure slots serve as spring structures with anchors, the spring structures with anchors being configured to release the residual stress, and to form a plurality of first through holes and second through holes in the center area, the plurality of first through holes act as tiny release-assistant holes, the tiny release-assistant holes act as stress releasing holes, the spring structures with anchors surround the bumps and the tiny release-assistant holes, the spring structure slots being located between the groove and the center area; Step 6, depositing a silicon rich nitride layer which covers bottoms and sidewalls of the second through holes, and covers parts of upper surface of the diaphragm adjacent to the second through holes, so as to form bumps; Step 7, etching parts of bottom of the groove until the upper surface of the multi-cavity silicon backplate to form an opening, and depositing two metal electrodes in the opening and the boundary area respectively, the two metal electrodes being located at a side opposite to the center area; Step 8, etching the lower surface of the multi-cavity silicon backplate to form a back cavity exposing the first dielectric layer at the bottoms of holes; Step 9, partially removing the first dielectric layer and the second dielectric layer to form a remaining portion on the boundary area to support the monocrystalline silicon diaphragm. Step 1, providing a diaphragm silicon substrate, and a multi-cavity silicon backplate with a center area and a boundary area surrounding the center area, a plurality of holes being arranged in the multi-cavity silicon backplate; Step 2, depositing a first dielectric layer on both upper and lower surfaces of the multi-cavity silicon backplate, the first dielectric layer covering bottoms and sidewalls of holes, and depositing a second dielectric layer on both upper and lower surfaces of the diaphragm silicon substrate; Step 3, bonding the lower surface of the diaphragm silicon substrate to the upper surface of the multi-cavity silicon backplate to form capacitor plates of the MEMS microphone; Step 4, thinning the diaphragm silicon substrate to form a monocrystalline silicon diaphragm of the MEMS microphone; Step 5, partially etching the monocrystalline silicon diaphragm and stopping the etch at the second dielectric layer to form a groove and a plurality of spring structure slots in the boundary areas, the spring structure slots and the monocrystalline silicon diaphragm near the spring structure slots serve as spring structures with anchors, the spring structures with anchors being configured to release the residual stress, and to form a plurality of first through holes and second through holes in the center area, the plurality of first through holes act as tiny release-assistant holes, the tiny release-assistant holes act as stress releasing holes, the spring structures with anchors surround the bumps and the tiny release-assistant holes, the spring structure slots being located between the groove and the center area; Step 6, depositing a silicon rich nitride layer which covers bottoms and sidewalls of the second through holes, and covers parts of upper surface of the diaphragm adjacent to the second through holes, so as to form bumps; Step 7, etching parts of bottom of the groove until the upper surface of the multi-cavity silicon backplate to form an opening, and depositing two metal electrodes in the opening and the boundary area respectively, the two metal electrodes being located at a side opposite to the center area; Step 8, etching the lower surface of the multi-cavity silicon backplate to form a back cavity exposing the first dielectric layer at the bottoms of holes; Step 9, partially removing the first dielectric layer and the second dielectric layer to form a remaining portion on the boundary area to support the monocrystalline silicon diaphragm.