In this article, we demonstrate a simple and cost-effective approach to fabricate antireflective polymer coatings. The antireflective surfaces have 3D structures that mimick moth compound eyes. The fabrication is easily performed via a one-step imprinting process. The 3D arrays exhibit better antireflective performance than 2D arrays over most wavelengths from 400 to 2400 nm. The reflectivity of the 3D arrays is lower than 5.7% over the all of the wavelengths, and the minimum reflectivity is 0.27% at a wavelength of around 1000 nm.