Abstract: The advanced DC electric detection is affected by many factors, which mainly affect the distribution of the whole current fields. The Ansoft Maxwell software was used to build up three models (the uniform medium model, tunnel excavation model and low resistivity layer model). The forward simulation showed that the current field distribution changed from concentric circle into spiral because of the tunnel excavation, the roof current intensity and current density were significantly less than the floor, and the current intensity and current density were concentrated near the heading face. Because of the geoelectric section, the current intensity and current density were refraction on the interface. By attraction of the low resistance bodies, the current intensity decreased and the current density increased in low resistance bodies, and current flowed along the bodies. On the contrary, the current intensity increased and the current density decreased outside of low resistance bodies, and the current field was concentrated on the corners. Affected by those, the whole apparent resistivity was decreased.