According to the theory of light diffraction and the moiré image-encoding, a new technology of image-encoding using non-key phase-only moiré method is presented in this paper. The unique reconstruction nature of the non-key moiré encoded phase-only plate manufactured with this method can not be imitated with other technologies. If it is used in the anti-counterfeit domain, the technology can dramatically enhance the anti-counterfeit capacity of produces.