Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a substrate, a dielectric layer over the substrate, a first metal gate structure in the dielectric layer and having a first width and a second metal gate structure in the dielectric layer and having a second width. The first metal gate structure includes a first metal electrode, and the second metal gate structure includes a second metal electrode. The second metal electrode includes a first conductive portion having a third width and a second conductive portion over the first conductive portion and having a fourth width. The fourth width is greater than the third width. The semiconductor device structure also includes two first source/drain portions at opposite sides of the first metal gate structure, and two second source/drain portions at opposite sides of the second metal gate structure.