A method for manufacturing a micro-electro-mechanical system (MEMS) device is provided. The method comprises: providing a semiconductor substrate, the semiconductor substrate having a metal interconnection structure (100) formed therein; forming a first sacrificial layer (201) on the surface of the semiconductor substrate, the material of the first sacrificial layer is amorphous carbon; etching the first sacrificial layer to form a first recess (301); covering and forming a first dielectric layer (401) on the surface of the first sacrificial layer; thinning the first dielectric layer by a chemical mechanical polishing (CMP) process, until exposing the first sacrificial layer; forming a micromechanical structure layer (500) on the surface of the first sacrificial layer and exposing the first sacrificial layer, wherein a part of the micromechanical structure layer is connected to the first dielectric layer. The method avoids polishing the amorphous carbon, shortens the period of production, and improves the production efficiency.