Abstract: This paper introduces the mechanism of applying Ground Penetrating Radar (GPR) in the advanced detection of subsurface conditions in the tunnel construction. In this case history, the GPR Model RIS\|K2 was used to determine geotechnical and geological conditions in the Longxing\|2 tunnel entrance excavation. Combined with other observations such as, topographical and exposed conditions at the tunnel face, the conditions of the area to be excavated are evaluated and predicted. The advanced detection by a GPR provides a basis for real\|time design of a safe excavation in tunnel construction. This paper sheds some light on the experience accumulated in applying GPR in the tunnel construction.