Analysis and correlation have been made on aeromagnetic data at diverse scales obtained from such areas as Liuzhou of Guangxi, North China plain, Xuefengshan of Hunan, Haizhou of Jiangsu, and Baiyinchang of Gansu by means of instruments of different sensitivities. The results obtained lead the authors to believe that, by raising the precision of aeromagnetic survey (from low precision to moderate or high precision) and magnifying the surveying scale, relatively abundant and detailed information on magnetic f teld might be obtained, and this will surely play a substantial role in investigating geological structure and improving ore-prospecting abilities.