A Micro-Electro-Mechanical-System (MEMS) microphone device includes a substrate, a MEMS microphone thin film, oxide layer. The substrate has a first penetrating portion. The MEMS microphone thin film is above the substrate and covered the first penetrating portion defining a first cavity. The MEMS microphone thin film includes an elastic portion and a connection portion. The elastic portion has a plurality of first slots arranged along the edge of the elastic portion and sequentially and separately. The first slots are penetrated two surface of the elastic portion, the surface are opposite each other. The connection portion is connected to the elastic portion and contacted the substrate. The oxide layer has a second penetrating portion. The oxide layer is on the MEMS microphone thin film and contacted the connection portion. A part of the MEMS microphone thin film is exposed through the second penetrating portion.