Abstract: AMT is different from the surface by observing the frequency of the electromagnetic signal to determine the value of underground resistivity method has low resistivity body, the advantage of better resolution, high efficiency, low cost, suitable for resource exploration, geophysical exploration is an important means. Audio magnetotelluric method (AMT) is an important resource exploration geophysical methods for low resistivity body it has better resolving effect. AMT law despite having low resistivity body better resolution and depth of great advantage, and has high efficiency, low cost, terrain conditions on small advantages; the drawback is uncontrollable and field source signal is weak, vulnerable to natural and man-made environmental impact, especially in areas of severe human disturbance. Disturbance-hit areas can CSAMT method, you can control the source audio magnetotelluric sounding method.This article describes the application of AMT law in a district of Gansu Copper Exploration. Mineralized alteration zones (ore) generally along fractures or lithological contact zone development, the performance of gradient zone in apparent resistivity section in FIG. AMT method can more accurately reflect the distribution of the ore body, it has good guidance for further geological work.