Taoshuping tunnel on LanzhouChongqing Railway is a Grade Ⅰ doubleline railway tunnel; it crosses waterrich fine silty sand strata. The surrounding rocks of the tunnel are bad and unstable. During the construction of Taoshuping Tunnel, large water inrush and softening of waterrich fine silty sand strata occur. As a result, doubledrift method is adopted to carry out drainage construction. The technical problem of the excavation of tunnel crossing waterrich fine silty sand strata has been solved and the deformation of primary support has been brought under effective control.