Research conclusions: It can be seen from the study that the ground penetrating radar wave reflected by the rock around tunnel lining has a larger amplitude and stronger signal disorderly than the wave reflected by tunnel lining． The waveform reflected by the steel structure in tunnel lining looks like hyperbolic，but the amplitude of the hyperbolic of the reinforced bar is relatively narrow，and the hyperbolic of the of the steel arch frame extends much vertically with small lateral extension． The waveform reflected by the lining cave or surrounding rock cave has characteristics of the confused phase axis of the reflected wave with repeated and stronger reflections and low frequency．