Abstract: Through analyzing the deformation characteristics of the tunnel, five main controlling factors, including the lateral pressure coefficient λ, the vertical pressure p of the surrounding rock, the cohesion C of the rock mass, the internal friction angle φ of the rock mass and the uniaxial tensile strength σ_t were selected. The orthogonal experiment was designed to study the influence of these five factors on the deformation and failure of the straight wall arch tunnel. The experimental results show that: the influence degree on plastic zone volume of the surrounding rock in straight wall semicircle arch tunnel is internal friction angle > lateral pressure coefficient > vertical stress > cohesion > tensile strength; the influence degree of the comprehensive deformation in the straight wall semi-circular arched tunnel is as follows, tensile strength > internal friction angle > lateral pressure coefficient > cohesion > vertical stress.