Abstract: Yeast industry provides enormous economic and social benefits for the sugarcane biomass industry. However, yeast industrial wastewater is characterized by high concentration of chemical oxygen demand (CODcr), high chromaticity, high concentration of sulfate and difficult biodegradation, which leads to many issues of the environment. The treatment process of wastewater has the problem that discharge water is difficult to reach the standard and its cost is too high, which has become a bottleneck restricting the development of domestic yeast enterprises. Biotechnology is currently widely used, but the results are still not up to standard. Therefore, biological treatment should be supplemented by other methods for in-depth treatment. In this paper, yeast wastewater was treated by adding photosynthetic bacteria to strengthen anaerobic sludge. The ultrafiltration membrane was used to filter the separated dialysate wastewater as the test object. A small UASB anaerobic reactor was designed. The initial MLSS (mixed liquid sludge concentration) value of the inoculated sludge in the reactor was 4 820 mg/L, and the reactor temperature was kept at 32 ℃. The hydraulic retention time was 48 h, and the influent pH value was controlled between 6.8 and 7.0. At the start-up stage of the anaerobic reactor, glucose, ammonium nitrate and potassium dihydrogen phosphate were used as C, N and P source, respectively, and an appropriate amount of trace elements were added to prepare a nutrient solution with a ratio of 300:5:1 of C:N:P. Yeast wastewater and nutrient solution were mixed and configured into water samples with mass concentration gradient of 3 000-3 500, 7 000-7 500, 10 000-10 500 and 14 000-15 000 mg/L, respectively. The water samples were added to the reactor in a gradient form from low concentration to high concentration, and the batch test was carried out until the organic concentration of wastewater reached the concentration of raw water. After the treatment effect of the reactor was stabilized, the photosynthetic bacteria were added to the domesticated anaerobic sludge, and the concentration of the bacterial suspension was 1.2×1010 mL-1 as determined by the Meish turbidimetry method, and the addition amount was 1 mL/L, the inflow was 900-1 000 mL with HRT of 48 h, and the continuous illumination by fluorescent lamp was used. After the reactor was stabilized, the water quality was tested and analyzed after continuous operation for 9 cycles. The CODcr and chromaticity changes of wastewater during anaerobic treatment，the OTU distribution of microorganisms during the addition of photosynthetic bacteria, the species of anaerobic sludge bacteria and sludge, and the changes in the number of archaeological clustering results were investigated. The results showed that the CODCr and chroma removal rates of yeast wastewater treated by anaerobic UASB reactor were significantly increased from 58.20% to 75.12% and 47.50% to 62.04%, respectively, which indicated that the effect of photosynthetic bacteria on the anaerobic biological treatment process has significantly increased. From the analysis of microbial diversity data, it was found that in the process of anaerobic sludge domestication and photosynthetic bacteria optimization, the dominant species was accumulated, the specificity was enhanced, and the number of species was reduced. Photosynthetic bacteria and other heterotrophic bacteria have a symbiotic relationship, and after the addition of the sludge, the dominant microorganisms of methane increased significantly, so as to improve the treatment effect of the anaerobic system. The results of this study provide a technical route for the effective treatment of high-concentration industrial organic wastewater.