Mobile hard disk is very sensitive to vibration because of unique mechanical working and the complexity of components. In view of inner structure and complying with quality equivalent principle, a 2.5 inch mobile hard disk finite element model is established based on ANSYS/LS-DYNA. The crashworthiness evaluate index is analyzed and set forward. The influence of drop angle is analyzed through simulation. In theoretically, the results are proven to be fundamental method of crashworthiness analysis, evaluation and design for mobile hard disk.