Abstract: Cubic boron nitride(c-BN)has a number of highly desired mechanical,thermal,electrical and optical properties.For this reason,there has been an extensive worldwide effort to synthesize thin films of c-BN.Recently there has been considerable progress in improving the deposition techniques and c-BN film quality.However unanswered question remains and process improvement is still needed.In this paper we introduce the useful applications of c-BN films and its microstructure,synthesis techniques,critically review the key experimental parameters controlling c-BN film formation and the mechanisms of c-BN formation.