Abstract：Geophysical exploration is conducted with controlled source audio magnetic telluric(CSAMT) method which is the main exploration method，VLF method，IP and TEM for some stations for the long deep-lying tunnel with a length of 20 km in west route of South-to-North Water Transfer Project. The exploration results with these four geophysical methods are introduced. According to the geophysical and engineering geological exploration results，the geological structure characteristics for the surrounding rock of the long deep-lying tunnel are interpreted；and the faults，fractures and some anomalies that may cause danger to the tunnel construction are explained.
