Abstract: A tapered thin-walled tube with rectangular cross-section used as energy absorber has been optimized from the point of energy absorption capability and weight efficiency. The specific energy absorption(SEA) and the ratio of the specific energy absorption to the initial peak force (REAF) have been considered as objective functions. The optimization process has been carried out by using the response surface method(RSM) based on the explicit Finite Element algorithm. The effects of geometric parameters of the tapered thin-walled tube with rectangular cross-section on two objective functions have been analyzed, and the optimal results have been obtained with two different optimization models. The research can be referred for the optimal design of the energy absorber and the further study.