摘要：The stratum lithology and geological structure of the highway tunnel in the mountainous areas of western China are complex,and the engineering geological conditions are *** the highway tunnel passes through different lithological strata,its structural design and construction technology are completely diff ***,in order to support the tunnel design and construction,the tunnel survey Among them,the identifi cation of the contact boundary between magmatic rock and metamorphic rock and the grade of surrounding rock is very *** magnetotelluric survey of the Mupi tunnel of Jiuzhaigou-Mianyang highway on G8513 line,2D forward numerical simulation,1D,2D,3D inversion,and engineering geological analysis,it is revealed that the electrical characteristics of each layer,focusing on the identifi cation of the contact boundary between magmatic rock and metamorphic *** study provides the electrical characteristics of the magmatic rock and metamorphic rock contact boundary of the Mupi *** is speculated that the boundary is revealed by the tunnel construction excavation,which verifies the correctness of the geophysical inversion model and provides a more detailed design basis for the tunnel design.I believe that taking the Mupi Tunnel survey as an example,through this research,it can provide detailed geophysical evidence for highway tunnels to distinguish between magmatic rock and metamorphic rock.