This paper reports the technology for producing agar from gracilaria by hightemperature and low alkali.The new technology involves alkali treatment,bleaching and extracting agar of graciria.The main features of this new technology are(1) Anthracene derivative increases the yield of agar by 3% in the NaOH treatment.(2) Amino sulfonic acid salt increases the gel strength of agar by 70g/cm2 inNaClO bleaching,and(3) Alkali treatment,bleaching and extracting agar ofgracilaria are conducted in the same tank.The o...