The present application discloses a method for manufacturing a semiconductor device, comprising: forming a local buried isolation dielectric layer in a semiconductor substrate; forming a fin in the semiconductor substrate and on top of the local buried isolation dielectric layer; forming a gate stack structure on a top surface and side surfaces of the fin; forming source/drain structures in portions of the fin which are on opposite sides of the gate stack structure; and performing metallization. A conventional quasi-planar top-down process is utilized in the present invention to achieve a good compatibility with the CMOS planar processes, easy integration, and suppression of short channel effects, which promotes the development of MOSFETs having reduced sizes.