A MEMS structure is provided. The MEMS structure includes a substrate having an opening portion and a backplate disposed on one side of the substrate and having acoustic holes. The MEMS structure also includes a diaphragm disposed between the substrate and the backplate and extending across the opening portion of the substrate. The diaphragm includes a ventilation hole, and an air gap is formed between the diaphragm and the backplate. The MEMS structure further includes a filler structure disposed on the diaphragm, and a portion of the filler structure is disposed in the ventilation hole.