Abstract: The equations of virtual work based on the theory of time increment were deduced to analyze stress-
strain states under fatigue loading conditions. A progressive damage method of predicting the fatigue life of mecha2nically fastened joint s in fibre- reinforced plastics was established , which is integrated fatigue material property degradation models. The three-dimensional Hashin-type fatigue failure criteria were int roduced into the method to detect damage for diverse damage modes. The criteria of the structure catast rophe and the sudden material property degradation rules including the correlation among four basic damage mechanisms were also established. The fatigue life , failure initiation , propagation and catast rophic failure of composite bolted joint s under tension2tension fatigue loading conditions are predicted by using the fatigue progressive damage method established in the paper . Excellent agreement is found between data obtained f rom this study and the experiment .