The invention discloses a method for purifying a eutrophic water body by utilizing saururus chinensis. The method comprises the following steps: 1) selecting underground stems or overground stems of the saururus chinensis; (2) horizontally placing the stem segments of the saururus chinensis in the eutrophic water body to enable the stem segments of the saururus chinensis to float and grow on the water surface; 3) fixing plants with bamboo poles; 4) when the seedlings reach 10-15cm high, transplanting the seedlings to a bank, a pond or an artificial wetland, an ecological floating bed, and thelike. The method of the invention utilizes nutrient elements in the water body to culture saururus chinensis, utilizes the saururus chinensis to purify the water body, can better remove total nitrogen, ammonia nitrogen, total phosphorus and chlorophyll a in the water body, and can achieve the effect of invading plant hyacinth in terms of purification efficiency and resistance to pollutants; The planting period and the viewing period of the traditional Saururus chinensis are prolonged, the ecological environment of the water body is improved, the wetland landscape effect is improved, the virtuous cycle of practical application, cultivation and reproduction and economic income generation of the Saururus chinensis seedlings is realized, and the market application value of the Saururus chinensis is greatly improved.