Abstract: The vibratory characteristic of the chip size package (CSP) is difficult to be abstracted to an accurate academic model because of its complexity, and because the classic resonance rules can not take the fuzziness of resonant region into account, the results of vibration reliability analysis are inaccurate for actual demands possibly. finite element method (FEM) is used to build up the vibration analysis model and analyze. Furthermore, base on the analysis of FEM, an academic fuzzy reliability analysis model of vibration is built up with the help of fuzzy theory. In the end, a calculating example of fuzzy reliability analysis of vibration testifies the proposed method and principle are effective.