The formation mechanism of rock disintegration phenomenon of surrounding rock in deep rock mass tunnels has always been highly controversial. The article explores this issue theoretically from the perspective of stress wave propagation. A physical model of stress wave propagation in the surrounding rock of a semi-circular tunnel was established. The wave equation of the surrounding rock area was solved, and the amplitude distribution of stress waves in the surrounding rock area of the tunnel showed a characteristic of wave attenuation. The innovative proposal was made for the width and theoretical depth of the fracture zone in the surrounding rock area of the tunnel. Taking Dingji Mine as the object, the theoretical calculation of the central radius of the surrounding rock partition was carried out and compared with the measured results. Most of the partition radii were in good agreement. The research results of this article have a certain promoting effect on the theory of zoning and fracturing of surrounding rock in tunnels.