Vehicle crashworthiness is one of the most important indicators to assess the automotive performance, which is directly related with passenger's life and safety. Therefore, more attention has been paid to improve the automotive passive safety. This paper presents the analysis method based on energy flow analysis to solve the automotive crashworthiness problem. The energy transfer model is built based on the constraints analysis for product performance and the rational energy flow element partition. According to the energy transfer model, the energy absorption of each component can be attained from the finite element crash simulation result and also the energy distribution relationship can be analyzed. Based on the analysis results, the full front impact crashworthiness of a car is improved by modifying the energy flow path and distribution. It also demonstrates that the method is effective to solve the automotive crashworthiness problem.