Abstract: In the various field components of frequency electromagnetic sounding of point double source （including CSAMT）,the point field E_x component has the advantages such as higher resolution,higher observation signal-to-noise ratio,need not near-field correction and so on.In the case of static offset resulted by the surface electricity inhomogereity,the static offset could be removed by the phase transfer.Therefore,the data processing and interpretation could not be limited to the mode of ratio resistance,resulting that the frequency electromagnetic sounding has larger flexibility and adaptability.