The invention relates to the Bell template digital image compression technology, in particular to a Bell template digital image coder and decoder (CODEC) method based on the W-Z structure. The problem of that a quainter design existing in the existing Bell template digital image CODEC method is not for global optimization and the like is resolved. The Bell template digital image coder and decoder (CODEC) method includes steps as follows that (I), a frame of the Bell template digital image is converted to four component images through the color spatial isolation, pixels in each Bell template is in color spatial conversion, original pixel values are displaced luminance components Y 1, Y 2, original reddish blue pixel values are displaced aberration components C r, C b, then the luminance components Y 1,Y 2 and the aberration components C r, C b are respectively separated and similar combinations are rectangular two luminance component image A, B and two aberration component image C, D. The Bell template digital image CODEC method based on the W-Z structure is reasonable in design and capable of displaying better rate-distortion performance under the condition with high speeds.