The present invention discloses a method for manufacturing a semiconductor device comprising the steps of: forming a plurality of source and drain regions in a substrate; forming a plurality of gate spacer structures and an interlayer dielectric layer around the gate spacer structures on the substrate, wherein the gate spacer structures enclose a plurality of first gate trenches and a plurality of second gate trenches; sequentially depositing a first gate insulating layer and a second gate insulating layer, a first blocking layer and a second work function regulating layer in the first and second gate trenches; performing selective etching to remove the second work function regulating layer from the first gate trenches to expose the first blocking layer; depositing a first work function regulating layer on the first blocking layer in the first gate trenches and on the second work function regulating layer in the second gate trenches; and depositing a resistance regulating layer on the first work function regulating layer in the first gate trenches and on the first work function regulating layer in the second gate trench.