The present invention provides a semiconductor structure, includes a substrate, a dielectric layer disposed on the substrate, a first gate structure and a second gate structure disposed in the dielectric layer, a hard mask disposed in the dielectric layer, where the hard mask covers a sidewall of the first gate structure, and covers the second gate structure, and a contact structure disposed in the dielectric layer. The contact structure at least crosses over the hard mask. The contact structure includes a first contact portion and a second contact portion. The first contact portion contacts the first gate structure directly, the second contact portion contacts the substrate directly, and the hard mask is disposed between the first contact portion and the second contact portion.