Abstract:The safe and reliable drainage system is an important guarantee for the disaster prevention and normal traffic of tunnel. However, for the urban underwater tunnel drainage system, there are no uniform and perfect specifications, guidelines and other related design requirements in China. Therefore, starting from the composition and characteristics of the urban underwater open-cut tunnel drainage system, the design requirements of tunnel drainage in the current specifications and guidelines are sorted out. On the basis of this, the corresponding design principles and standards are proposed. Five design essentials have been summarized, such as strictly controlling the scope of catchment water, perfecting the rainwater and wastewater collection system, enhancing the tunnel drainage toughness, effectively ensuring the discharge outlet and improving the flood prevention capacity of the pump house in order to provide the design guidelines and technical support for the design of urban underwater open-cut tunnel drainage systems.