Fatigue reliability of graphite/epoxy composite laminates under uniaxial spectrum stress is studied using the modified β-method. A number of cumulative damage models are adopted to construct the limit state equation for the laminates in the reliabilty analysis. Statistics of fatigue life distributions of the laminates under cyclic stresses of constant amplitudes obtained from tests are used for the reliability assessment of the laminates under spectrum stress. The accuracy of the modified β-method in fatigue reliability prediction is then verified by experimental multi-stress level fatigue life data. The applicabilities of the modified β-method and the cumulative damage models in fatigue reliability prediction are discussed. It has been found that several of the adopted cumulative damage models may be applicable for fatigue reliability analysis of composite laminates under spectrum stress.