Objective To investigate the optimization design of laminated plastic foam system made of expanded polystyrene (EPS) and expanded polyethylene (EPE). Methods Based on experimental data, the constitutive relationships of EPS and eEPE were identified respectively. According to their constitutive models, the drop impact model of EPS in series with EPE was established and solved by Newton-Raphson iteration method. Finally, the solving process of serial packaging structure optimization was introduced using numerical examples, and the optimal packaging structure was obtained. Results The calculated acceleration-time curve agreed well with the experimental data. Conclusion The serial method in this paper offers reference for other serial structures in solving dynamic responses.