In order to improve the demulsification efficiency,reduce the processing cost and decrease the damage to the environment during demulsification of oily emulsions,nanoparticles(NPs) have attracted much attention in the field of demulsification,due to their strong controllability and multiple advantages.First,the demulsification mechanisms for magnetic and non⁃magnetic nanoparticles in demulsification were reviewed,providing strategy for the development of new demulsifiers. Secondly,the preparation methods and applications of nanoparticles were summaried.Finally,based on the development of crude oil extraction technology,the current advantages,remaining doubts and difficulties of nanoparticles in the field of demulsification were points out,as well as, the prospects for future research.