Abstract A new nonstationary signal analysis method，namely, the local mean decomposition (LMD) is introduced in this paper. By using LMD, any complicated signal can be decomposed into a set of product functions whose instantaneous frequencies own physical sense and each of which is a product of an envelope signal and a purely frequency modulated signal, thereby the complete time-frequency distribution of the original signal can be obtained. In this paper, firstly the LMD method is introduced, and then the simulated signal is analyzed by LMD and satisfied results have been obtained. At last, the LMD method is compared with EMD method and the results indicated that the LMD method is superior to the EMD method in some respects, as in boundary effect and iterative times.