On basis of the practice of the treatment of the karst water in the anticline and syncline structures and the waterproofing construction of Yuanliangshan tunnel and the practice of waterproofing construction of Tiefengshan karst tunnel on Wankai highway in Chongqing, the article describes the treatment of karst water and karst caves and the waterproofing construction of the tunnel portion with huge volume of highpressured water and makes discussions on the principles of waterproofing construction, the selection of construction methods and the construction techniques of karst tunnels with high water pressures, which can provide reference for the construction of similar tunnels.