In order to improve the purification capacity of the purification area in the internal circulation aquaculture pond, a photosynthetic bacterium named GR01 was isolated and purified from the bottom mud of internal circulation aquaculture pond in Tongnan District, Chongqing. The strain was classified and identified by morphological observation, physiological and biochemical identification, 16S rDNA gene sequence analysis and absorption spectrum scanning. The absorbance (A660) of GR01 was measured at 660 nm under different temperature, pH and salinity, and the optimal culture conditions were determined. The ammonia nitrogen (NH3-N), nitrite nitrogen (NO2--N), total nitrogen (TN) and total phosphorus (TP) were determined to explore the decontamination ability of the strain to the water in the purification area of the inner circulation aquaculture pond under the indoor simulated conditions. The results showed that GR01 was Rhodocista pekingensis, the optimal growth temperature was 28℃, the optimal pH was 8.0, and the optimal salinity was 10‰. The removal rate of the strain to NH3-N, NO2--N, TN and TP in the tail water was 57.42%, 28.74%, 32.67% and 32.85%, respectively. The results showed that GR01 had a significant removal efficiency to nitrogen and phosphorus, and the removal efficiency to ammonia nitrogen was the highest, which provided basic data for tail water purification in internal-circulation pond aquaculture and had a potential application prospect when combined with the internal-circulation pond aquaculture mode.