Research conclusions ； With three bench method, the large - sized construction machines can work rapidly, flexibly and synchronically on many working faces. It is easy to choose suitable three bench method for different geological conditions to satisfy the requirement of construction safety. Of course, there are some disadvantages of three bench method, but these disadvantages can be overcome by controlling the bench length, stabling the arc foot, perfect support in advance and proper drainage. The practices show three bench method is a successful method in reinforcing weak surrounding rock of mountain tunnel of passenger dedicated line and is worth using widely.