Abstract: Based on model of Pasternak elastic foundation，shear buckling strength of web of lattice-enhanced foamsandwich structure was analysed and probed under pure shear stress，due to the existence of foam core． The applicable condition of the analytic model was discussed，whose rationality was confirmed in comparison with the data of FEM model． The results show that the analytic model can match with the FEM model very well if the core thickness could be guaranteed to some degree． The existence of the core can enhance the web stability effectively． The shear stiffness provided by foam core to the web stability is still of great significance，even if the Young's modulus of the core material is low． But with the increase of ratio of height to thickness of web，and the augmentation of the young's modulus of the core material，the normal stiffness from the foam core play a more controlled role on the web shear stability． The ratio of length to height could be omitted for the perspective of engineering application．