Abstract: The theoretical form of shear buckling strength of honeycomb core was shown based on the principle of minimum complementary energy and shear buckling theory of thin plate. By regarding the cell wall as a beam with elastic supports, the shear buckling strength of honeycomb core considering elastic supports was got from interpolating the strengths of clamped and simple supports. Then, three point short beam bending tests were performed to obtain shear buckling strength of Nomex honeycomb core. The tests' results were compared with theoretical results and agree well with theoretical solutions, which verified our theory. Finally, the anisotropy of shear buckling strength and the influence of honeycomb height on shear buckling strength were investigated. The results show that there is no influence of honeycomb height on the anisotropy of shear buckling strength, while both the longitudinal and transverse shear buckling strengths decrease with the increasing height of honeycomb and the decreasing ratio drops gradually.