Provided are a method and device for decoding and encoding supplemental auxiliary information of a three-dimensional video sequence. The method includes: obtaining supplemental auxiliary information for constructing a stereo-pair from a three-dimensional video sequence bitstream, the supplemental auxiliary information being used for indicating that the stereo-pair is constructed from a reconstructed three-dimensional video sequence, and the reconstructed three-dimensional video sequence being obtained by decoding the three-dimensional video sequence bitstream. The present invention solves the technical problem in the prior art that degraded displaying quality of a constructed stereo-pair appears because of the lack of supplemental auxiliary information in a three-dimensional video sequence bitstream, and achieves the technical effect of improving the display quality of a constructed stereoscopic video.