Abstract: Floating bed ofPolygonum cuspidatum was constructed, the polydatin content ofP. cuspidatum in the sediment and water were measured by HPLC. The results showed thatP. cuspidatum grew normally in water, and the vigorous root inside floating bed could sprout naturally after overwintering, and could be continuously used for a certain time; the removal rate of TN, TP, NO3--N and NH4+-N of 3.5%P. cuspidatum (the total weight of P. cuspidatum /water) detected on the 20th day was 69.4% , 71.3% , 90.3% and 74.1% , respectively. P. cuspidatum had the highest removal rate of NO3--N among water-quality indexes, then was TN, TP, NH4 +-N and NO2--N. The content of polydatin in soil-growing roots was about 10 times as that in water-growing roots. The content of polydatin in soil-growing leaves was about 50% higher than that in water-growing leaves.