Driven by the dual strategies of the comprehensive "antibiotic ban" in feed and the "low-carbon" transformation of animal husbandry developing natural, green and efficient antibiotic-substitute feed additives has become an urgent demand for the sustainable development of the breeding industry. As natural active macromolecules derived from marine algae, algal polysaccharides have become one of the research hotspots in the field of feed additives due to their unique structural characteristics and multi-dimensional biological functions. This paper systematically reviewed the classification, structural characteristics and core biological functions of brown algae, red algae, green algae and microalgae polysaccharides. This paper reviewed the research progress of their application in monogastric animal and ruminant production, focusing on their application potential and mechanisms in regulating rumen fermentation, enhancing immune function, improving lactation performance and maintaining intestinal health in dairy goats. This paper identified the key problems existing in current research and industrial application, and proposed targeted future research directions and industrial application suggestions, aiming to provide a systematic theoretical reference for the scientific application of algal polysaccharides in the green and healthy breeding of dairy goats.