The aquaculture industry adopts high-density aquaculture, which easily deteriorates the environment of the aquaculture pond, especially when the weather changes, the growth and decline of microorganisms in the fish pond often causes abnormal changes in water quality causing disease and even death. In addition, because of the high organic matter discharged after the animals are ingested or the utilization of nutrient elements is reduced, the pollution to the surrounding environment is even greater. The continuous deterioration is eventually solved by a large amount of water exchange. In addition to wasting water resources, it is also extremely unfriendly to the surrounding environment. This year's plan is to use duckweed to purify the water quality to establishment of the ecological model for pond culture. With the good purification ability of duckweed, in addition to reducing excessive changes in water quality during the breeding process, the duckweed that grows can be recycled and reused as a secondary product to provide aquaculture animals for feeding and utilization. In addition to monitoring changes in water quality, oxidation-reduction potential of sediments, and recording water consumption and duckweed growth, absorption and yield, the use of duckweed was also discussed. As a result, the concentration of various nitrogen compounds in the water is within the range suitable for fish growth. It is estimated that if the flow-water aquaculture pond is changed to this mode, about 60,000 metric tons of water per hectare can be saved per year. A total of 1,046 kilograms of duckweed was harvested. During the breeding process of Wu Guo fish, duckweed was fed for 1 day every 5 days, which can save about 190,000 yuan in feed costs per hectare per year. A total of 1,046 kilograms of duckweed was harvested. During the breeding process of Wu Guo fish, duckweed was fed for 1 day every 5 days, which can save about 190,000 yuan in feed costs per hectare per year. In addition, due to the rapid reproduction of duckweed, the carbon sink is estimated to be about 39.3 metric tons per hectare of aquaculture ponds.