A UV nanoimprint lithography process and its apparatus that are able to repeatedly fabricates nanostructures on a substrate (wafer, UV-transparent plate) by using a stamp that is as large as or smaller than the substrate in size are provided. The apparatus includes a substrate chuck for mounting the substrate; a stamp made of UV-transparent materials and having more than two element stamps, wherein nanostructures are formed on the surface of each element stamp; a stamp chuck for mounting the stamp; a UV lamp unit for providing UV light to cure resist applied between the element stamps and the substrate; a moving unit for moving the substrate chuck or the stamp chuck to press the resist with the element stamps and substrate; and a pressure supply unit for applying pressurized gas to some selected regions of the substrate to help complete some incompletely filled element stamps.