Hymenachne aquatic grass, Hymenachne acutigluma was planted in the wastewater from intensive striped catfish (Pangasianodon hypophthalmus) cultivating ponds containing 2.1 mg N/L, which was enriched with a serious of inorganic phosphorus (P) concentrations. The experiment was arranged in a completely randomized design with three replications in the net house for 42 days. The results showed that P concentrations did not significantly affect the growth of Hymenachne. The presence of high P concentrations resulted in the increase of P content in plant tissues leading to higher P absorption at the P levels of 8 and 10 mg P/L. H. acutigluma removed 12.1–27.6% P from 88.3–95.9% P in the wastewater of striped catfish pond. This result indicated the low concentrations of N (2.1 mg N/L) and of 1 –10 mg P/L were not optimal for the growth of H. acutigluma.