The present invention discloses a nanoimprint apparatus and method useful in the cost-effective mass production of nanostructures over large areas on various substrates or surfaces, especially suitable for non-flat substrates or curved surfaces. The nanoimprint apparatus is composed of a wafer stage, a vacuum chuck, a substrate, a UV-curable nanoimprint resist and the like. The method implementing large-area nanopatterning based on the apparatus includes the following steps: (1) pretreatment, (2) imprinting, (3) curing, (4) demolding, (5) post treatment and (6) transferring of imprinted patterns. By utilizing the apparatus and the approach, large-area, and/or high-aspect-ratio micro/nanostructures can be mass produced, especially on a non-flat substrate or a curved surface or a fragile substrate at low cost and high throughput.