Abstract: This study investigated the effects of aeration/light time distribution on the nitrogen removal efficiency of algal-bacterial granular sludge(ABGS), aiming to provide technical support for efficient nitrogen removal from ionic rare earth mine tailings in southern Jiangxi Province. The nitrogen removal performance and operational energy consumption of ABGS were compared across six parallel reactors with different operational modes: M1(aeration), M2(aeration → light), M3(light → aeration), M4(aeration → light → aeration), M5(light → aeration → light), and M6(light). The steady-state effluent total inorganic nitrogen(TIN) concentrations ranged from 84 to 234 mg/L, with corresponding TIN removal efficiencies ranging from 6.4% to 66.4%; M6 achieved the highest removal efficiency. Significant nitrate accumulation(225～231 mg/L) was observed in the effluents of M1–M4, where longer aeration times led to more severe nitrate accumulation. The effluent of M5 exhibited both nitrate and nitrite accumulation; shortened aeration time partially inhibited nitrification but notably enhanced algal assimilation, resulting in a TIN removal efficiency of 32%. In contrast, the effluent of M6 showed substantial accumulation of ammonia nitrogen and nitrite, indicating that nitrogen removal was primarily driven by algal assimilation. The energy consumption per cycle for each mode ranged from 0.222～ 0.480 kW·h, with unit ammonia nitrogen removal energy consumption ranging from 1.169～1.920 kW·h/g and unit TIN removal energy consumption ranging from 1.354～17.550 kW·h/g. Among these, Mode M6 exhibited the lowest total energy consumption per cycle, as well as the lowest unit energy consumption for ammonia nitrogen and TIN removal.