Abstract: A structural similar finite element model of honeycomb material is proposed according to its compression mechanics, and numerical simulations are conducted to validate the equivalence of computational results of actual and structural similar models at the conditions of axial compression of honeycomb material and blast shock response of sandwich structures. The results show that the structural similar model can represent the macro-behaviours of honeycomb material and increase the computational efficiency dramatically. Hence, analysis and design optimization of honeycomb sandwich structures under blast loadings become feasible via the proposed modelling approach. Based on the structural similar modelling method, an optimization of a honeycomb sandwich structure under blast loadings is conducted for lightweight design using the adaptive response surface method, and the structural area density is reduced effectively under the given blast protection requirements.