This paper deals with the magnetic parameters of rocks (ores) frommagmatic-hydrothermal ore deposits and the data-processing of primaryhaloes. It is found that a certain relationship exists between the magneticproperties of rocks (ores) and the hydrothermal leakage haloes of some ele-ments. By evaluating its characteristic values, we can obtain information insuch aspects as element association, ore-forming stage and mode of occurrenceof the orebody. Such information is of great geological-ore prospecting signifi-cance.