Hollow polymer nano- or microspheres are of great interest in the fields of drug delivery, cosmetics, catalyst carrier, and microencapsulation. This review is devoted to the progress made in recent years in the fabrication and application of hollow polymer nano and microspheres. The preparation methods including emulsion processing, self-assembly technique, emulsion polymerization, and templating method, and their applications are presented. Fundamental aspects of these formation processes and their effects on the particle properties are also discussed in this paper. Polymer nano and microcapsules are one  of the most extensively used materials for encapsulation system. This review also provides a brief description of current production methods and introduces encapsulation applications of formed particles.