Abstract: Micro expression is a fast facial movement,which usually lasts for 1/25 to 1/5 second.It reveals a real emotion that people try to suppress and conceal.In this paper,facial action coding system(FACS) is firstly analyzed briefly,and then the experimental study of artificial micro expression recognition is explored.Secondly,the acquisition,generation and usage of micro expressions are comparatively summarized based on the existing automatic micro expression recognition database.Thirdly,the comparative studies of recognition results,technologies,advantages and disadvantages with an emphasis on automatic micro expression recognition methods are also reviewed.Fourthly,the evaluation measures of micro expression are discussed.Fifthly,a typical application of using micro expression clues to deception detection is addressed.Finally,several issues worthy of further study and possible directions of development are concluded.