Abstract: In order to improve the culture density of photosynthetic bacteria and optimize the feeding process,the online redox potential system was used to guide the flow of the main carbon source sodium succinate during the photosynthetic bacteria culture process. The different supplemental concentrations of sodium succinate and the feeding mode were investigated. The results showed that oxidation reduetion potential(ORP)rebound could be used as a signal that the bacteria stopped growing due to the lack of the main carbon source sodium succinate. Compared with batch culture,photosynthetic bacteria grew optimally when the rate of sodium succinate was 0.08 g·(L·h)^-1,and the cell density increased from 0.611 g/L to 0.927 g/L. The intermittent carbon source addition process based on ORP was superior to continuous flow addition,and the final microbial culture density could increased to 1.46 g/L. The feeding culture process of photosynthetic bacteria based on ORP greatly improved the production efficiency and provided certain guiding significance for the subsequent industrial production.