In order to efficiently attenuate the intensity of the blast wave in the tunnel, the design idea of setting up a continuous number of diffusion chambers in the tunnel is proposed, and the influence of the structural parameters of the multi-stage diffusion chamber on the wave dissipation efficiency and the propagation attenuation characteristics of the shock wave with different characteristics in the tunnel containing the multi-stage diffusion chamber are systematically discussed based on the numerical simulation method. The results show that the increase in the number of diffusion chambers can effectively improve the wave dissipation efficiency of the tunnel, and the peak pressure of the shock wave after passing through the three-stage diffusion chamber pit is 81.08% lower than the peak pressure of the straight pit without diffusion chamber of the same length, while the spacing between the diffusion chambers has a limited effect on the wave dissipation efficiency of the tunnel. Under the condition that the total length of the diffusion chamber is equal, the tertiary diffusion chamber has the best attenuation effect on the shock wave compared with a single long diffusion chamber and the secondary diffusion chamber. With the increase of shock wave pressure under the same positive pressure duration, the wave dissipation efficiency of the multi-stage diffusion chamber pit slowly increases. Under the same peak overpressure condition, the wave loss efficiency of the three-stage diffusion chamber pit decreases greatly with the increase of positive pressure time, but it can still maintain a wave loss efficiency of 43.38% under 1000 ms positive pressure time. The research results can provide technical support for the application of multi-stage diffusion chamber structure in tunnel engineering.