Abstract: Sialic acids are widely distributed in many organisms, which are usually found at the end of non-reducing oligosaccharide.Sialic acids are known to play an important role in many processes of life activities.Owing to their potential edible and pharmaceutical applications, large scale production of sialic acids are needed.The physiological function, application and manufacturing method of sialic acids were introduced and the future directions of sialic acids were put forward.