Abstract: In order to increase the estimation accuracy of the time-delay, an optimized estimation algorithm, which is based on the higher-order cumulant theory and the dynamic statistics, is proposed. Firstly, the time-delay sequence of a single pair of discharge signals is estimated by higher-order accumulation theory. Secondly, the time-delay sequences of the groups of discharge signals are accumulated and then the average value was calculated. Thirdly, the accuracy time-delay was estimated. The simulation results indicated that the existent algorithm brings in a great error when the signal-noise ratio(SNR) of the discharge signals are smaller than 5 dB, whereas the new algorithm succeeds in estimating the time-delay of the signals as low as -20 dB, and the needed accumulation statistics is no more than 100. At last, the effectiveness and practicality of the algorithm are verified by estimating the time-delay of the measured corona discharge signals at a remote distance of 100 meters.