This paper uses analytical calculation analysis and numerical simulation research methods to study the pressure relief of tunnels. Blasting pressure relief achieves the purpose of improving surrounding rock support conditions. The high ground stress of the surrounding rock of the tunnel is transferred to the surrounding rock far away from the surface of the tunnel by loosening blasting to relieve the pressure so as to achieve the purpose of reducing the stress of the surrounding rock and protecting the tunnel. Finally, the simulation results of the internal force of the lining structure are found to be consistent with the analytical research and the numerical research results.