Abstract: To realize high-accuracy measurement parameter of low frequency oscillation signal in Power System, the Local Mean Decomposition (LMD) algorithm is applied to the low frequency oscillation signal detection in power system for the first time. This algorithm overcomes the incapability for the Fourier algorithm to deal with non-stationary signals, as well as the difficulty in choosing Wavelet. LMD algorithm can be accurate to abstract the dynamic oscillating performance and abundant transient fault information from the non-stationary signal, The amplitude and frequency curve, not only can accurately locate the disturbance moments butt also can detect the voltage fluctuation amplitude of typical low frequency oscillation signal. The simulation waveform was influenced by "end effect" smaller. Simulation results show that LMD Algorithm is effective and has better locate accuracy and computing speed than the HHT algorithm.