Abstract: To compare the physiological and ecological characteristics of inoculant of photosynthetic bacteria and Rhodopseudomonas palustri, we analyzed the degradation effects of the inoculant PG and the strain PSB-1 with different initial amounts of bacteria on ammonia nitrogen (\begindocument\rm NH^+_4\enddocument-N), nitrite nitrogen (\rm NO^-_2-N), nitrate nitrogen (\rm NO_3^--N) and phosphate (\rm PO_4^3--P) in experimental water. Then we studied the dominant bacteria composition of inoculant of photosynthetic bacteria PG, as well as the number of bacteria and microbial community composition in experimental water at the end of the experiment by high-throughput sequencing. The results show that the inoculant PG group had certain degradation effects on\rm PO_4^3--P,\rm NO_3^--N and\rm NO_2^--N in experimental water. The maximum degradation rates of PG for\rm PO_4^3--P,\rm NO_3^--N and\rm NO_2^--N were 40.98%, 28.28% and 20.12%, respectively. Moreover, the strain PSB-1 group only had certain degradation effect on\rm NO_2^--N and\rm PO_4^3--P. The maximum degradation rates of PSB-1 were 14.19% and 9.88%, respectively. The dominant bacteria of the inoculant PG belonged to Rhodopseudomonas sp.. After 7 d of experiment, the number of bacteria and microbial community structure in the experimental group changed, and the number of bacteria in the water increased, forming a microbial structure with heterotrophic bacteria as the dominant bacteria. It is indicated that the inoculant of photosynthetic bacteria PG has better effect on the degradation of water quality factors than R. palustris PSB-1. However, there is a certain gap between both things and the reported degradation efficiency of photosynthetic bacterial strains.