The present invention provides a semiconductor structure, including a substrate having a first fin structure and a second fin structure disposed thereon, a first isolation region located between the first fin structure and the second fin structure, a second isolation region located opposite the first fin structure from the first isolation region, and at least an epitaxial layer disposed on the side of the first fin structure and the second fin structure. The epitaxial layer has a bottom surface, the bottom surface extending from the first fin structure to the second fin structure, and the bottom surface is lower than a bottom surface of the first isolation region and a top surface of the second isolation region.