When a tunnel construction passes through the surrounding rock with karst caverns, the displacement change characteristic of rock mass is different with the common tunnel. On the basis of the present construction situation of Sinitic mountain tunnel method, the new concepts of ahead displacement, releasing displacement in excavating, early displacement and the later displacement, which are the new division from the tunnel excavation displacement three-dimensional effect, have been proposed. With the new understanding of the displacement three-dimensional effect characteristics, the influence of horizontal karst caves on displacement characteristics of surrounding rock has been analyzed with the numerical experimentation. The research results indicate: (1) the horizontal karst caverns will cause the earlier period and radial displacement in excavation to increase obviously, and the displacement release rate also increases; (2) the horizontal? karst caverns will cause the surrounding rock integrity to be weakened, and the early period displacement will mainly concentrates inside the 2.0 times of hole diameter, its later displacement will basically complete after the tunnels is excavated to the distance of 1.5 times of tunnel’s diameter.