The invention relates to a method for improving an 
eutrophic water body by planting vegetables on a water surface, which comprises the following steps of: (1) selecting 
fresh water of which the 
nitrogen content is more than or equal to 0.5 mg / L, 
phosphorus content is more than or equal to 0.05 mg / L and 
potassium content is more than or equal to 0.5 mg / L in a 
water body; (2) enclosing a vegetable planting area; (3) arranging the vegetable planting area; (4) manufacturing a floating planting 
bed; (5) selecting vegetable varieties; (6) planting vegetables; (7) managing, namely controlling the speed of 
water flow according to the growth vigor of the vegetables and a detection result of 
water quality, so that compared with a water inlet in the planting area, at a water outlet, the 
total nitrogen content is reduced by 30 to 90 percent, the 
total phosphorus content is reduced by 20 to 70 percent, and the 
potassium content is reduced by 10 to 50 percent while the growth vigor of the vegetables is ensured; and (8) selecting the vegetable varieties which is suitable to be planted in different seasons, and planting in turn throughout the year. In the method, the 
eutrophic water body is improved effectively by a biological cleaning method, and compared with physical and chemical means of managing the 
eutrophic water body, the method has obvious effect and low 
investment cost and is convenient to popularize and perform large-scale planting; and the vegetables are planted without applying 
fertilizer and spraying pesticides, so a new 
pollution source is not generated, and the planted vegetables reach the standard of green organic vegetables. By the method, 
resource utilization is maximized, and vegetable baskets of people are abundant while the eutrophic 
water body is managed. The production management and monitoring are convenient, so the method is particularly suitable for the large-scale planting.