The anti-explosion effects and anchored mechanism of tunnels reinforced by bolts were studied by numerical analysis. Comparing with compression-stress curve of the experiments and numerical simulation on the same location of the vault, it indicates that the simulation results are reliable. By contrast the vault displacement of anchored tunnel and unlined tunnel, it can be found that the vault displacement of the tunnel is significantly reduced through the reinforcement with anchor bolts. By comparing the crack distribution of the anchor tunnel and unlined tunnel, it shows that cracks of unlined tunnel are significantly thicker and wider than that of the anchored tunnel, which indicates that the anti-explosion effects of anchor rods are better. It can be known that the anchored bolts supporting can take effect of reinforcement and anti-explosion according to the time-histories curve of the anchor-head.