Bieyancao Tunnel is a key project and listed as level I risky tunnel on Yichang-Wanzhou Railway. This tunnel's geological condition is very complex especially the developed karst cave and underground river. It is considered that serious geological disasters called "LiuMao"  phenomena are most likely to occur in construction process. The article introduced that with the help of comprehensive ahead geological forecasting ,this tunnel assured the safety and avoided the geological hazard accidents. It also summarizes the comprehensive geological prediction technology of risky tunnel based on the practice.