Abstract: Based on the Paris-Erdogan crack propagation model,the effect of random parameters on the crack propagation model was considered.The reliability model for crack propagation of rotating shaft in rotating machinery was presented by the crack length failure criteria.The first four moments of state function were derived from the random perturbation theory and the Kronecker algebra.The reliability of crack propagation was determined by using the stress-strength interference theory and the fourth moment method.The reliability sensitivity analysis of crack propagation was studied by using the matrix calculus theory and sensitivity technique.