Abstract: A method is presented to assess the vibration reliability for blade design.The method based on Campbell diagram and the concept of PFTA (Probability Fault Tree Analysis) is used to improve conventional assessment methods,and aims at developing an effective method for resonance identification and assessment of the characteristics of blade resonance system,which consists of multiple resonant interception on the Campbell diagram at or near the operating speed.Much information will be obtained from this PFTA analysis,and it is useful for designer to improve the vibration characteristics of a given blade in design and in elimination of failure blade yielded from vibration fatigue.