Taking into account the demands of hyperspectral remote sensing (RS) image retrieval and processing, some encoding methods of spectral vector including directencoding, feature-based encoding and tree-based encoding methods are proposed and compared. In direct encoding, based on the analysis of binary encoding and quadvalue encoding, decimal encoding is proposed. It is proved that quadvalue encoding and decimal encoding are suitable to fast processing and retrieval. In absorption feature-based encoding method, five common metrics are compared. Because locations of reflection Pabsorption features are sensitive to noise, this method is not very effective in retrieval. In tree-based encoding methods, bitree, quadtree, octree and hextree are proposed and iscussed. It is proved that 2-level octree and 2-level hextree are more effective than bitree and quadtree. Finally, quadvalue encoding, decimal encoding, 2-level octree and 2-level hextree are proposed in spectral vectors encoding, similarity measure and hyperspectral RS image retrieval.