Reliability analysis of structure fatigue has two assignments: a. To forecast lifetime of the structure on given reliability level, b. To evaluate reliability level of the structure on given service conditions, material features and designing dimensions. It aims at evaluating the structure’s designing quality and providing a basis for designing improvement or manufacturing. At mean time, it provides instruction to updating management by parameter of failure rate under given fatigue lifetime.Lastly, in form of tables, this paper presents the predicting results of fatigue lifetime of pantograph V500 based on different reliability levels at 500km/h and the predicting results of reliability level of Pantograph V500 under lifetime of 1,200,000km which provide direction of design, manufacturing and general management for Pantograph V500.