Abstract: The comprehensive geological forecast model combined with TSP, ground penetrating radar and advance borehole method was used to predict the inlet section of Balangshan tunnel, and contrast analysis was conducted for the forecast results, geological data and the exposing situation of excavation. The result showed that the comprehensive geological forecast model had a favorable effect, the safety of tunnel construction was ensured, and this model had higher practicability and effectiveness. This article had theoretical significance and practical value for the research of comprehensive geological forecast in tunnels.