Abstract: The wavelet approach for multiple decomposition of gravity anomalies is modified using multiscale edge analysis theory,and a separation method based on multiscale edges is proposed.The experimental results show that the new method has the same advantages of multiple decomposition method,and can be used to simultaneously perform vertical and lateral separation of anomalies.A proper degree for decomposition can be determined according to the distribution of multiscale edges of each source with respect to the scale,it is very useful to isolate single anomaly.Shipborne gravity data in southwest of Ryukyu subduction zone are analyzed.The result has good coherence with the geological tectonics in this area.