This paper deals with the Controlled Source Audiofrequency Magneotelluric method (CSAMT) applied to gold-copper deposits, in the Chinkuashih area, northern Taiwan. This is the very first time CSAMT has been used for precious metals exploration. Theoretically, the CSAMT method is used to receive the E-field and the orthogonal H-field which is produced by the magnetic field induced by transmitting the step current source into the subsurface by grounded bipole. For calculating the apparent resistivity, the Cagniard resistivity formula was employed. Finally the resistivity layers of each station will be obtained by means of matching the field apparent resistivity curve with the model one.