Abstract: A new optical encryption technique based on double random phase computer-generated hologram of asymmetry fractional Fourier transform is presented.In this method,two phase functions are introduced into the input image and its fractional domain spectrum before the fractional Fourier transform hologram of original object of different order in the x and y directions.The transformed result is coded and fabricated into computer-generated hologram.In order to reconstruct the encoded image,two random functions and two orders must be matched.Because the decoding keys are added to four from two,anti-counterfeiting intensity can be improved greatly when it is used to encrypt image or anti-counterfeit.