The embodiments of the disclosure provide a patterning method, which includes the following processes. A target layer is formed on a substrate. A hard mask layer is formed over the target layer. A first patterning process is performed on the hard mask layer by using a photomask having a first pattern with a first pitch. The photomask is shifted along a first direction by a first distance. A second patterning process is performed on the hard mask layer by using the photomask that has been shifted, so as to form a patterned hard mask. The target layer is patterned using the patterned hard mask to form a patterned target layer. The target layer has a second pattern with a second pitch less than the first pitch.