Nanoporous anodic aluminum oxide (AAO) templates are fabricated using an anodization method. The mean diameter of the nanoporous AAO templates is 100 nm. A molded plastic thin film with nanostructure is fabricated using AAO template as a mold insert by nanoimprint. The surface properties of the molded plastic thin film obtained using various processing parameters in nanoimprint are discussed. The contact angle of the molded polycarbonate (PC) thin film with the nanostructure exceeds that without the nanostructure. The molded PC thin film (with nanostructure) with a hydrophobic surface is formed and has a water contact angle of 128.5 degrees. The use of AAO to prepare a mold insert for nanoimprint supports the formation of a nanostructure in the molded PC thin film and effectively increases its antireflectance.