One Tunnel is the stick point of the planned railway from Chongqing city to Huaihua city. It will traverse the Guanyinxia anticline. Based on monitoring data about groundwater line and groundwater quality and the analysis of hydro-geological conditions in the Tunnel, The paper discusses the groundwater dynamic characteristic and its controlling processes and the hydrodynamic conditions of the Karst water flowing system at Guanyinxia anticline. Furthermore, the influence of Tunnel drainage for the groundwater following system was also estimated. It will be advantage for the further hydro-geological research in this ares.