Abstract: The reliability design of fatigue strength in designated service life of machine ele- ments is investigated. As the fatigue strength in designated service life of most metals is in negative skewed distribution, it will incline to unsafety in using the traditional calcula- tion method, by which the fatigue strength is treated as normal distribution. Using the Monte Carlo simulated method or the graphical method as introduced in this paper, the results obtained will be more closing to the practical performance.