Abstract: On the basis of a series of failure models, the Monte Carlo sampled method is used to test the fatigue life distribution of a multi-detail (MD) structure. The simulated result shows the fatigue life of a MD structure follows the same distribution as the single detail (SD) structure, but unprecise in the tail. The distribution parameters of the MD structure are deduced when the fatigue life of SD follows the log-normal distribution. The MD’s expectation and variation are lower than the SD’s if the details are the same and lower than the maximal value of the SD if the details are different. Assuming the fatigue life of the SD follows the two parameter Weibull distribution, the MD has the lower scale parameter and the same slope, the different MD’s scale parameter is lower than the maximal scale parameter, and the slope is larger than the minimum slope. Finally, the fatigue scatter factor of a MD structure is discussed.