Abstract: The intersecting cavern is a common structural form of underground protective projects, and its safety and stability performance directly control the service performance of the whole protective projects. The dynamic response of a typical equal span orthogonal cavern subjected to ground shock is studied through numerical simulation. The results show that the deformation and damage range of the intersecting cavern are significantly larger than those of the unidirectional cavern with the same span under the same depth and load. With the increase of the peak value of the ground shock, two V-shaped intersecting plastic belts with symmetrical centers are gradually formed at the intersection of the straight wall of linings, and the arch foot and the bottom of the straight wall are gradually yielded. With the increase of the cavern span, the increment of the vault settlement and the peak particle velocity of the arch at the intersection increases. The damage mainly focuses on the straight wall of small-span tunnel, and on the vault of large-span tunnel. The influence range of the tunnel intersection is 1.6 times the tunnel span from the intersection center, and the arch foot and the straight wall bottom of the intersection are the weak positions. Locally thickening the supporting structures is suggested to improve the stability of the tunnel.