Effects of nutrient levels in sediments and water column on growth of floating\|leaved plant Trapa quadrispinosa were evaluated through a 2×2 factorial outdoor experiment. The results showed that nutrient levels of sediments had significant effects on the growth of T. quadrispinosa. For the relative growth rate (RGR), the percentage increase in plant height and rosette diameter, and the biomass of aquatic and anchoring roots, they were significantly greater in high\|nutrient sediments than in low\|nutrient sediments. Increased concentrations of nutrients in water could stimulate the growth of plant T. quadrispinosa. Nutrient addition (especially for phosphorus) in water resulted in a more significant plant growth in the low\|nutrient sediments than in the high\|nutrient sediments. The study suggests that eutrophication of water body and accumulated nutrients in sediments with swampy tendency may be causes that the stock biomass of floating\|leaved macrophyte Trapa quadrispinosa in East Taihu Lake has increased rapidly recently.