Aiming at the end effect problem existed in the signal decomposition process of Local Mean Decomposition(LMD), to further improve the instantaneous frequency precision of EMD signal measurement and to restrain the strong impact brought by end effect on signal analysis, the improved LMD algorithm based on the Gene Expression Programming(GEP)was described．In order to analyze the effect of the improved algorithm more precisely, comparison was made with the other three kinds of suppression methods, including mirror extension method.The simulation results indicate that the improved LMD algorithm based on GEP are superior to the other three traditional improved methods, and the divergence degree of each components both ends proves to be the minimum after the signal decomposition．In addition, the algorithm restrains the end effect brought by the decomposition process more effectively, and measures the instantaneous frequency of the original signal more precisely, which proves to be of higher application value．