Based on life prediction of fatigue crack growth in a powder metallurgy, the residual strength interference model and life interference model are proposed to analyze the reliability of the fatigue crack growth. The reliability of the fatigue crack growth life of single inclusion is analyzed by the advanced first order and second moment method. In order to obtain the crack growth reliability of multiple inclusions existed in the structure, a new model, where the mean value of the random inclusion position is distributed uniformly, is presented. Comparing with the available model, where the mean value of the random inclusion position is at the center of the volume occupied by the corresponding inclusion, the new position distribution model is more safe and more suitable for engineering application. In the illustration, the above reliability method is applied to analyze the reliability of a powder metallurgy turbine disk. The results show that the position of the inclusion in the turbine disk has significant effect on the failure probability of the crack growth.