Abstract: Seed mucilage consists of pectin polysaccharides that are secreted by the Golgi apparatus in epidermal cells to the cell cavity and cell walls of the seed coat, which swells considerably upon wetting. Mucilagineous seeds commonly are found in species of Brassicaceae, Asteraceae, Plantaginaceae and several other flowering plant families. Many taxa with mucilageous seeds occur in deserts. Seed mucilage is ecologically advantageous for seed dispersal, germination, seedling development and protection of seed, and thus it is an adaptation of plants to deserts and sand dunes. In addition to furthering our understanding of the ecological and evolutionary aspects of desert plants to their environment, research on mucilaginous seeds will be helpful in building a model system for exploring gene control mechanisms of carbohydrate synthesis and secretion, secondary cell wall biosynthesis and cell morphogenesis. In this paper, we review recent advances on mucilaginous seeds, with emphasis on (1)chemical composition of seed mucilage; (2)morphological characteristics of mucilaginous seed coats and mucilage; (3) biochemical processes in and genetic regulation of differentiation of mucilage-secreting cells, mucilage biosynthesis and mucilage secretion in the seed coat; and (4) ecological significance of seed mucilage. Finally, prospects for further research in this area are discussed. Our purpose is to promote research on the seed biology of desert plants in China and to provide additional justification for protection of biodiversity and for ecological conservation in the desert region of northwest China.