Augmented reality display devices, as a wearable smart device, significantly enhance the experience of the real world by superimposing virtual information on the real field of view, and therefore have very strict requirements for device size and weight. Micro- and nano-optical elements, which are optical elements with thickness or size of the nanometer or micron scale, provide new ways to reduce the size and volume of systems while possessing powerful optical field modulation capabilities. This paper first reviews the principles and modulation of several types of typical micro- and nano-optical elements, and then discusses the technical paths and applications of micro- and nano-optical elements in augmented reality devices and looks into future developments.