The invention discloses a method for extracting polysaccharide from overground parts of polygonatum cyrtonema. The method comprises the following steps: collecting overground parts of polygonatum cyrtonema, and crushing the dried polygonatum cyrtonema raw materials; adding petroleum ether into the obtained polygonatum cyrtonema powder, carrying out uniform shaking, then carrying out refluxing in water bath, carrying out suction filtration to recover the petroleum ether, adding an ethanol solution into filter cake, carrying out reflux extracting, then carrying out suction filtration, collectingthe filter residue, and drying the filter residue; uniformly mixing the filter residue of the overground parts of polygonatum cyrtonema with distilled water, carrying out suction filtration, and collecting the filtrate; slowly adding ethanol into the filtrate, continuously carrying out stirring, discarding the supernatant, collecting the precipitate, sequentially adding ethanol, acetone and diethyl ether into the precipitate, carrying out washing for multiple times, and carrying out drying by volatilizing; and dissolving the polysaccharide precipitate in distilled water, and repeatedly carrying out deproteinizing to obtain powder which is refined polysaccharide of polygonatum cyrtonema. Compared with the yield by single polysaccharide extraction of polygonatum cyrtonema rhizomes, the yield of the polygonatum cyrtonema polysaccharide can be increased by 40% by using the overground parts of polygonatum cyrtonema. Through applications of the device, polygonatum cyrtonema resources can bemore fully utilized, and the supply path of the polygonatum cyrtonema polysaccharide is also broadened at the same time.