This paper presents a novel invertible 3D maps based image encryption method. A 2D gray-level image is represented as an array of gray level values of the pixel, which can be considered as the third dimension. An invertible 3D maps are presented and utilized for image encryption. The proposed scheme combines the permutation and the substitution using the invertible 3D maps. All bits in the image data matrix are permuted during the operation of the 3D maps. Therefore 2D positions of image pixels are permuted, and 1D grey level values of the pixels are also substituted, that is two processes of image encryption, permutation and substitution, are performed simultaneously. The security abilities of the scheme are analyzed evaluated in detail, which shows that it has high level security. Simulation results validate the effectiveness of the proposed image encryption method.