The invention provides a manufacture method for an MEMS (Micro-electromechanical Systems) device, and the method comprises the following steps: providing a semiconductor substrate, wherein a metal interconnection structure is formed in the semiconductor substrate; forming a first sacrifice layer on the surface of the semiconductor substrate, wherein the first sacrifice layer is made of amorphous carbon; etching the first sacrifice layer to form a first groove; covering and forming a first dielectric layer on the surface of the first sacrifice layer; thinning the first dielectric layer by utilizing a chemical mechanical grinding technology until the first sacrifice layer is exposed; forming a micro-electromechanical structure layer on the surface of the first sacrifice layer; exposing the first sacrifice layer; and connecting the part of the micro-electromechanical structure layer with the first dielectric layer. By utilizing the manufacture method, a sacrifice dielectric layer is firstly formed, then, the sacrifice dielectric layer is imaged, and the dielectric layer is formed, therefore, the amorphous carbon does not need to be grinded, the production period can be shortened, and the production efficiency is greatly improved.