The invention relates to a method for direct separation and preparation of
agarose and
agaropectin from
agar. The method comprises the following steps: 1, respectively preparing an
agar solution and a
polyethylene glycol (PEG) solution, at a constant temperature, mixing, stirring, allowing to stand, and generating a precipitate; 2, centrifuging the
mixed solution, to obtain the precipitate and a supernatant; 3, washing the precipitate with pure water and
anhydrous ethanol, and filtering to obtain a
filter cake and a filtrate; 4,
drying the
filter cake, and smashing to obtain
agarose; 5, adding
ethanol into the concentrated supernatant, allowing to stand, and thus obtaining a precipitate; 6, centrifuging the
mixed solution, and filtering to obtain the precipitate and a filtrate; 7,
drying the precipitate to obtain
agaropectin; 8, merging the filtrates, concentrating under reduced pressure, collecting fractions, and recycling
ethanol; and 9, further concentrating under reduced pressure to a
molten state, cooling to solidify,
drying, and recycling PEG. The method not only obtains
agaropectin during the process of
precipitation preparation of
agarose, but also solves the problems of recycling the precipitating agent PEG and ethanol, thereby achieving the effects of cyclic utilization and
environmental protection.