A crashworthiness optimization method based on Kriging metamodeling is proposed. Construction of the Kriging metamodeling method and its evaluation of the accuracy criteria are discussed firstly. Transient nonlinear finite element method is employed to model the crush process of thin walled tube. Secondly, radius and thickness of the tube are defined as independent design variables and the global approximation model is built based on Kriging metamodling with the maximum impact load and the maximum crush length defined as optimal object and constraints function respectively. Then, an updating strategy of Kriging metamodeling is introduced to improve accuracy of the global approximation and the optimization process is introduced too. Finally, both object and constraint functions obtained through global approximation model are coupled with genetic algorithms to perform the objective optimization.