The high-rate discharging performance of lithium titanate batteries is a crucial aspect of their functionality. Under high-power demands, the discharge rate, which is defined as the ratio of discharge current to the maximum capacity, can exceed 50 C or higher. This study investigates the evolution of incremental capacity (IC) curves and frequency response characteristic of 2 Ah lithium titanate batteries subjected to aging cycles at 50 C. The results provide a new indicator to assess the fading of the state of health (SOH) of lithium titanate batteries during ultra-high-rate discharge cycles.