Effects of different cutting intensities on the growth, photosynthesis and the purification efficiencies on nitrogen and phosphorus of the Lolium multiflorum by hydroponics experiment method were studied. The results were shown as followings: 1) Cutting could promote regeneration capacity of the Lolium mutiflorum, and sprout regeneration rate in C2 (stubble = 5 cm) achieved 2.78 cm x d(-1) after being cut 5 to 13 d, which was significantly more than zero-cutting (0.88 cm x d(-1)). The height, standing-biomass, productivity of cutting groups were significantly more than zero-cutting. Their compensation capacities were raised with the increase of cutting intensity, and the sprout height, total biomass of the serious cutting groups were 40.6-44.0 cm, 31.6-37.2 g, which indicates that the serious cutting is good for the biomass cumulation of the Lolium multiflorum. 2) Different cutting intensities have obvious effects on the chlorophyll contents of Lolium multiflorum: the chla and chla/chlb in C2 were about 1.85 mg x g(-1), 3.18, which was highest in treating groups, while they were lowest in zero-cutting. 3) The fluorescence chorophyll parameters had a significant changes in the different cutting intensities. With increasing cutting intensity, the values of phi PS II and ETR were significant increased: the phi PS II and ETR in C2 were about 1.13 and 1.09 times of those in zero-cutting, indicating cutting could improve the photosynthetic capacity of Lolium multiflorum. 4) The purification efficiencies on TN, NH4+ -N, TP and COD had a significant increase with the cutting intensities increase, and the purification rate on TN, NH4+ -N, TP and COD of C2 was 1.07,1.20, 1.05,1.44 times more than zero-cutting respectively. 5) About 2-5 cm of stubble was the best cutting height of Lolium multiflorum, which can applied a technical references for ecological bed management.