Abstract: There were potential risks of pylon collapse and civilian injuries during the construction of the Guanyinshan tunnel beneath a 110 kV high-voltage pylon which is served as power supplying for the Yue Gang water pipeline project. In order to control surface subsidence, surface grouting, double-layer advance grouting pipes, and double-side-drift seven-step excavation were adopted during construction. In this paper, the stability of the high-voltage pylon is analyzed and a dynamic adjustment of the construction scheme is performed according to monitoring information. This tunnel was driven through under the high-voltage pylon safely and successfully, ensuring the normal water supply to Guangdong province and Hong Kong.