Abstract: The herringbone buckling(double rib buckling) of strip was a serious flatness defects, and its mechanism of production was still unknown. A new explanation about herringbone buckling was put forward in this paper, and based on Airy stress function and S.Timoshenko’s principle of least work, a new mechanical model of herringbone buckling was established, and the stress field in strip prebuckling was obtained in this paper, the mathematic model of critical buckling stress was also achieved by Galerkin’s principle of virtual displacement, the path generation of post-buckling was found with Perturbation-Variational Solution, and the mode of post-buckling was in good accordance with the buckling mode of Finite Element Method. The results of the analysis could play a important role in prediction of herringbone buckling and its angle of inclination on strip rolling line.