In this paper,to improve the encryption efficiency of the image,a double image e ncryption method based on three-step ph ase-shifting digital holography and chaotic random phase encoding was proposed. The two images to be encrypted were firstly encoded into the amplitude and phase of a complex image.Then the complex image was encoded into a noise-like patter n by the chaotic random phase masks placed in the object light path.Finally,th e noise-like pattern interfered with the reference light to generate three holo g rams in which the two original images were hidden.In this proposed method,the initial values and control parameters of the chaotic system can replace the rand om phase masks to serve as the secret keys,which makes the management and trans mission of the secret keys become more convenient.In addition,the diffraction distance and incident wavelength can also serve as the additional secret keys,w hich can further improve the security of the proposed method.Simulation results demonstrated that any useful information about the two original images cannot b e decrypted if any of the secret keys is incorrect.Additionally,the simulation r esults also demonstrated that the proposed method can resi st noise attack and occlusion attack with high robustness.