To analyze the influence of explosion-proof wall on antiknock performance for large-span reticulated shell structures, propagation of blast shock waves around explosion-proof wall was simulated with finite element software ANSYS/LS-DYNA. The ALE (Arbitrary-Lagrange-Euler) algorithm was determined due to good agreement with experiment. A kiewitt8 single-layer reticulated shell of refinement was established to simulate the dynamic responses of structure considering explosion-proof wall subjected to external blast loading. The response rules of the structure with varied height, position of explosion-proof wall and span ratio of reticulated shell were obtained to analyze the effects of explosion-proof wall and structure on circulating and reflecting action of blast shock wave. Dangerous height of explosion-proof wall including specific values was proposed, which could provide reference for reasonable defense design of reticulated shell structure.