Based on the collapse accident of a shallow buried loess tunnel in Ningxia, this paper first discusses and analyzes the collapse failure mechanism and mode of the shallow buried loess tunnel. Then, based on the on-site collapse situation, the causes of the tunnel collapse are analyzed and the disposal plans are proposed. Finally, the disposal effect is evaluated through numerical simulations and on-site monitoring. The results show that the vulnerability of loess itself, adverse terrain, disturbance du-ring shallow tunnel construction, and heavy rainfall infiltration jointly lead to the formation of a certain range of loess soft and collapsible zones in the surrounding rock above the tunnel. The original tunnel support structure cannot resist the degraded surrounding rock, and the deformation and structural stress of the surrounding rock increase significantly. Among them, the settlement of the arch crown increases by 91.8%, and the initial positive bending moment at the arch shoulder increases by 60.7%; The instability and failure of the excavation face in loess strata can be divided into two modes: the instability and failure of the palm face reaching the weak and collapsible zone, and the instability and failure of crossing the entire weak and collapsible zone. Combining the finite element simulation and on-site monitoring verification, the comprehensive anti-collapse treatment technology of "temporary support system plus arch replacement plus advanced pipe shed grouting reinforcement" has shown significant application effects.