The invention relates to a hirudo high-density culture method with a steel frame floating net, and belongs to the technical field of large-scale hirudo culture. The hirudo high-density culture method with the steel frame floating net is characterized in that supporting steel frames, floating net cages, foam cylindrical floaters and the like are arranged, by means of the eight steps of the hirudo high-density culture method with the steel frame floating net, high-density, high-yield and high-quality hirudo culture is achieved, and the survival rate and finished product output rate of hirudo are greatly increased. The yield per mu can maintain stability within about 1000 kg to 1250 kg, the yield is increased by 150%, and the economic benefit of culturists is greatly improved. An aerator drives the floating net cages to swing and enhances fluctuation quantity of water bodies to rapidly complete water body exchange; an adequate amount of hydrophyte is added to enhance water purification capacity of the water bodies in culture areas, water transfer is conducted at the right moment, and the cleanliness of the culture water bodies is kept. The problems that for an existing conventional culture mode, the water body exchange is difficult, the hirudo is quite prone to infection due to the fact that the water temperature is uncontrolled, the water deteriorates and the temperature of the water bodies is high, and the quality of the survival hirudo and the yield per unit area are greatly affected are solved, and the hirudo high-density culture method with the steel frame floating net is suitable for culturing the hirudo in lakes, reservoirs, paddy fields and ditches.