The invention discloses a rhizome section fast propagation method for polygonum hydropiper. The method comprises the following steps: (1) drawing materials from the wild, namely selecting a polygonum hydropiper community with good wetland growth vigour, and excavating rhizomes in a soil layer underground, wherein the rhizomes are kept complete while sampling and loading; (2) selecting rhizome sections, namely washing the rhizomes taken back from the wild with running water for removing soil; (3) soaking with rooting powder solution, namely putting the cut rhizome section into the rooting powder solution to be soaked; (4) preparing a substrate, namely blending equivoluminal river sand and peat soil to prepare a culture substrate for later use; (5) preparing a seedling bed, namely paving the substrate on the seedling bed; (6) sowing, namely horizontally placing the selected rhizome sections into a sowing furrow, and then covering with the culture substrate, wherein the rhizome sections are connected end to end; (7) cultivating, namely watering once everyday, so that the substrate keeps wet but water is not logged; and (8) transplanting, namely excavating plants from the substrate when new roots grow on the rhizomes, and transplanting the plants into soil. The method disclosed by the invention is convenient, operation is easy, propagation period is short, germination rate reaches 90%, and transplanting survival rate reaches 95%.