Abstract: Based on the theory of wavelet transform and multi-scale decomposition of magnetic anomalies are analyzed.The theore-tical model and practical analysis indicated that the wavelet and multi-scale analysis are usefule to establish the decomposed anomalies correlated to certain geological sources.The same method is utilized to process the actual data of a coal field.The processing result extrudes the anomalies of the fritted rock and compresses the irregular interference,which provides a more precice geological explanation.