The present invention provides a method of forming Fin-FET. A substrate with an active region and a dummy region are defined thereon. A plurality of first fins and second fins are formed in the active region, and a plurality of dummy fins are formed in the dummy region and the active region. A first active region is provided in the active region. A revised first active region is formed by extending the first active region to cover at least one adjacent dummy fin. Next, a first dummy region is provided in the dummy region. A first mask layout is formed by combining the revised first active region and the first dummy region. A first patterned mask layer is formed by using the first mask layout. A first epitaxial process is performed for the first fins and the dummy fins exposed by the first patterned mask layer.