Abstract: According to the deformation physics mechanism of tunnels in deep soft rock,a number of simulation analyses with the software discontinuous deformation analysis(DDA)was carried out on the rule of displacement and deformation of surrounding rock caused by changes of factors influencing excavation deformation of tunnels,including the ground stress,angle of fracture plane,elastic modulus of rock block,poisson ratio of rock block,cohesion of fracture plane,internal fiction angle of fracture plane,tensile strength of fracture plane.The results showed that the ground stress is the most important factor influencing deformation of surrounding rock,and there is critical value in many indicators influencing deformation of surrounding rock.The importance sequence of rock characteristic influencing displacement and deformation of surrounding rock was reached.The opinion was put forward that the key of surrounding rock control in deep soft rock tunnels is to reinforce surrounding rock in time to improve its residual strength and optimalize supporting form to shape key bearing structure to prevent the development of deformation area.