Abstract: The Masangshao tunnel passes through a section with complicated geological condition. The ground is rich in karst and underground water, and has many faults and fractured zones. In the process of construction, a comprehensive geological prediction was adopted. It included the TSP203, geologic radar, regular geologic analysis and advance horizontal boring. They verify and supplement one another. The paper compares the geological prediction of Masangshao tunnel with the information revealed after excavation. This comparison shows the accuracy of comprehensive geological prediction. The above-mentioned practice has certain lessons and guiding significance to geological prediction of similar projects.