In order to address the issue of deterioration of phosphorus removal performance caused by competition between denitrifying glycogen-accumulating organisms (DGAOs) and denitrifying phosphorus-accumulating organisms (DPAOs) for carbon source in denitrification and phosphorus removal technology, three groups of the same specification of SBR reactor were set up in the experiment. Changes in the conversion of internal carbon source, denitrification and phosphorus removal performance as well as the ratio of abundance of DGAOs to that of DGAOs were explored by comparing the operation under the different anaerobic/anaerobic sections with different HRTs. The results show that with an anaerobic/anoxic HRT of 90 min/170 min, the abundance ratio of DGAOs to DPAOs is 1.97, with the maximum internal carbon storage (182.81 mg/L) and phosphorus release (31.72 mg/L). The removal rates of COD, TP, and NO^-₂-N are 94.69%, 96.37%, and 90.40%, respectively. Conversely, with an anaerobic/anoxic HRT of 50 min/210 min, the insufficient anaerobic time results in inadequate uptake of carbon by the microorganisms, with the lowest endogenous carbon storage (141.59 mg/L). Additionally, the prolonged anoxic time causes DGAOs to utilize stored glycogen (Gly) for denitrification, adversely affecting their growth and resulting in the lowest abundance ratio of DGAOs to DPAOs (0.49). When an anaerobic/anoxic HRT of 130 min/130 min, the abundance ratio of DGAOs to DPAOs increases to 2.63. However, the excessive anaerobic time detrimental to the storage of the internal carbon source of DPAOs, resulting in effluent TP levels exceeding 0.5 mg/L. Additionally, the insufficient anoxic time negatively impacts denitrification, causing the removal rate of NO^-₂-N decrease to 81.05%. At an HRT of 50 min/210 min, a higher proportion of DPAOs is more conducive to PN secretion, promoting granulation with an average particle size of 517.6 μm. In contrast, the larger proportion of DGAOs at 130 min/130 min enhances PS secretion, which is not conducive to granulation, resulting in a smaller average particle size of 255.3 μm. At an anaerobic/anoxic HRT of 90 min/170 min, the average particle size of the sludge is 480.1 μm, establishing a balance between DGAOs and DPAOs, leading to optimal system stability and pollutant removal performance.