Abstract: The fatigue life prediction model with given survivability for peened butt weld of 16Mn steel is investigated. It is shown by the test results that at a given equivalent stress amplitude, the fatigue life of peened butt welds of 16Mn steel follows the lognormal distribution. The expressions of S-N curve and P-S-N curve are given in this paper. Furthermore, the method of fatigue life prediction with given survivability under variable amplitude has been given in this paper. The life prediction results have been substantiated by the tests. It is pointed out that the above-mentioned method can be taken as a new model of fatigue reliability evaluation for weldments.