Abstract: The function of constant amplitude median Sa-Sn-Nf surface is established. And the two-dimensional statistical Miner's rule is proposed for reliability based prediction of fatigue life under variable araplitude loading. Then, Wirsch-ing's model is restudied, and it is found that Wirsching's model is not of self-consistency. Therefore the modification of Wirsching's model is performed based on statistical Miner's rule. In the end, an example of application is presented, show-ing that the two-dimensional statistical Miner's rule is very convenient and feasible in fatigue reliability anaiysis for engi- neering structures.

Key words: Median St-Sm-Nc surface Two- dimensional statistical Miner's rule Wirsching's model, Fatigue Reliability