The invention provides a preparation method of a
semen plantaginis
polysaccharide extract. The preparation method comprises the following steps: (1)
raw material treatment, namely
drying semen plantaginis, removing impurities, crushing, breaking hulls, adding
petroleum ether, and carrying out
reflux degreasing, so as to obtain residues; (2) rough extraction, namely adding
distilled water with the weight of 6-12 times of weight of the residues and a cosolvent with the weight of 0.1-0.2 time of weight of the residues, carrying out ultrasonic assistant dissolving and concentration, adding
ethanol, and carrying out
alcohol precipitation and
centrifugation, so as to obtain a precipitate, sequentially and respectively washing the precipitate with absolute ethyl
alcohol and
acetone, dissolving the precipitates with
distilled water, and carrying out
dialysis, concentration and
freeze drying, so as to obtain a precipitate A; and (3) extraction, namely sequentially and respectively washing the precipitate A with absolute ethyl
alcohol and
acetone, dissolving the precipitate A with
distilled water while heating, carrying out
centrifugation, extracting supernate, removing color matters and proteins, and carrying out reduced pressure concentration, so as to obtain the
semen plantaginis extract. According to the preparation method, the semen plantaginis is subjected to
hull-breaking pretreatment and is subjected to secondary extraction through assistant dissolving by virtue of the cosolvent and ultrasonic
waves, and the prepared extract is high in
polysaccharide content, and the extraction process is simple.