A novel image transforming method called Reconstruction Transform is proposed, which can make the double random phase encryption image become non-negative integer value. Reconstruction transform includes two stages, pre-processing and spectral shifting. It′s major characteristic is that, compress the interger image to become complex image of half-sized before applying spectral transform to the original image, thus reducing the calculation space in the following steps. The proposed method has the advantage of joint image compression and encryption. Compared with the chaotic image encryption scheme, the cipher-text image of the proposed scheme has lower information entropy. Experimental results show that this method has high security, the decrypted image of this method has little distortion and the cipher-text image has a certain degree of robustness to additive noise attack.