Large bending-buckling deformation frequently occurs in tunnels with soft-hard thin-bedded surrounding rock, posing a serious threat to tunnel construction and operational safety. To reveal its disaster-inducing mechanism, field investigations, FLAC3D numerical simulations, and theoretical analysis were conducted to investigate the effects of strata dip angle, soft-to-hard rock layer thickness ratio, and interlayer bond strength on bending-buckling deformation. The results show that: (1) The strata dip angle significantly affects the spatial distribution of bending-buckling deformation. With increasing dip angle, the deformation mode gradually transitions from vault-dominated deformation to sidewall-dominated deformation. Under the same dip angle, an increase in the soft-to-hard rock layer thickness ratio weakens the regulatory effect of interlayer bond strength on deformation and makes the maximum deformation tend to become consistent. (2) The displacement at the maximum deformation position of the surrounding rock increases with the soft-to-hard rock layer thickness ratio, but the increase is constrained by the interlayer bond strength. As the bond strength decreases, this increase is significantly reduced.(3)Three subtypes of the bending-buckling large deformation mechanism are proposed: bending–coordinated deformation–buckling, bending–delamination tensile cracking–squeezing, and bending–extrusion buckling–collapse. As the soft-to-hard rock layer thickness ratio increases and the interlayer bond strength decreases, the deformation mechanism gradually evolves from the first subtype to the third. This study reveals the classified evolution law and coupled disaster-inducing mechanism of bending-buckling large deformation in soft-hard thin-bedded surrounding rock, providing new insights for differentiated support design.