Abstract: The provision for the calculation of the pressure of unsupported surrounding rock based on the weight of collapsed rock in Code for Design of Tunnel is not applicable to the NATM engineering practice. If the knowledge of lining load is constrained by the statistical formula of landslides, it's hard to conceive the design of tunnel by using probabilistic limit state method under the reliability theory. Hence, it is suggested more engineering analogy cases be added, relevant structural calculations be removed and numerical method be widely used in the stability analysis of surrounding rock considering the Code for Tunnel Design, providing a qualitative guidance for the tunnel design.