The invention provides decoding and de-interlacing system and method of a CVBS. A two-dimensional luminance and chrominance separating device receives a sampled CVBS corresponding to a field image signal, and a two-dimensional luminance signal and a two-dimensional chrominance signal is separated and generated in the sampled CVBS. The two-dimensional chrominance signal is converted into a two-dimensional color difference signal by a chrominance-color difference converter. A zooming synchronizer is used for respectively carrying out synchronous operation on the sampled CVBS, the two-dimensional luminance signal and the two-dimensional color difference signal to respectively generate a synchronous CVBS, a synchronous two-dimensional luminance signal and a synchronous two-dimensional color difference signal. A temporary storage device is used for temporarily storing the synchronous CVBS, the synchronous two-dimensional luminance signal and the synchronous two-dimensional color difference signal. A three-dimensional luminance and color difference separating, noise-removing and de-interlacing device is used for executing three-dimensional luminance and color difference separation, noise removal and de-interlacing operation to generate a picture frame signal.