Abstract: Azolla filiculoides Lamk and Salvinia natans as the floating aquatic plants were selected as the experimental materials，through the static water control experiment，their purification effect with application of rare earth cerium on removing paranitroanilinum，2， 4-dinitroaniline and 3-nitroaniline were determined by HPLC. The results showed that the two plants were both effective on removal of the three aniline compounds in the water. The trace rare earth element cerium can promote the degradation of three aniline compounds by Azolla filiculoides Lamk and Salvinia natans， among which application with 5 mg·L-1 cerium solution was most effective for Azolla filiculoides Lamk on three aniline compounds， showing the degradation rate of 89.60%， 89.86% and 89.69%， respectively. However， the inhibitive effect appeared under high concentration of cerium. In general， the removal effect of Azolla filiculoides Lamk on three aniline compounds was superior to Salvinia natans.

Key words: aniline, cerium, Azolla filiculoides Lamk, Salvinia natans, HPLC