MapGIS was used to perform data extraction in such key areas of Peru as Acari, Huarato, Hierro Acari and Pampa de pongo. Various kinds of aeromagnetic data-processing were performed for aeromagnetic anomalies, and characteristics of the magnetic field before and after the processing were compared with each other. In combination with geological data, the distribution of the structures and ore deposits in the key ore districts was explained. Test and verification show that the practically exploited key ore districts are coincident with the conclusions reached by inverse analysis, thus proving the accuracy and effectiveness of the aeromagnetic method.