Abstract: A model of leaf spring composed with ten spring laminations is established by the language of APDL. The model is loaded with pre-stress, static stress and Grade B Road stress, then the results is calculated. Finally, applying the PDS unit of ANSYS, the reliability of leaf spring is worked out. As an important hanging form in the vehicle, the leaf spring is widely used in auto, besides the reliability of a car mostly depends on it. So, it is necessary to deeply study its designing method and reliability[1,2].