Abstract: As one of the three major alginates, agar is widely used in food, biology, medicine, daily chemical and other industries. The products processed by agar, such as agarose, agar oligosaccharide, etc., also have very high application value. In this paper, the research progress in agar extraction technology and deep processing were reviewed. The advantages and disadvantages of agar extraction technologies of agar, such as high temperature and pressure method, alkaline extraction technology, and enzymatic assisted extraction technology were described, and the main application scope of agar deep processing was analyzed, and the development direction of agar extraction technology and deep processing were forecasted, in order to provide reference for the further application of agar in various fields.