When forced power oscillation occurs in a power system，location and elimination of disturbance sources is of great significance for the secure and stable operation of the system.The electromechanical disturbance caused by the forced power oscillation travels along the transmission line.According at the time delay characteristics of disturbance waveforms at different locations，a novel method for locating disturbance sources using the least mean square（LMS）time delay estimation method is proposed.In this method，the starting of forced power oscillation is tested by the second-order difference method，and the travelling sequence of the disturbance is obtained by calculating the time delay of the disturbance waveforms at different buses， thus the disturbance source is located according to the sequence.The proposed method only needs the wide area measured data and is capable of on-line application.The validity of the proposed approach is verified by simulation results of a four-machine two-area power system and in the Central China power grid.