An analytical method is proposed to predict the fatigue life of the beam with multiple cracks based on the Paris equation.In the modal analysis process, the segment of cracks is replaced with bending springs, a new method for solving natural modes of the beam with multiple cracks is proposed based on the transfer matrix method, and the effect of the number, locations and depths of cracks on the natural frequency of the cracked beam is analyzed. In the vibration fatigue analysis, the effect of the number of cracks on the crack-tip stress intensity factor under harmonic excitation is analyzed. Considering the interaction of cracked beam vibration and fatigue crack growth, the effect of the number and the location of the cracks on the cracked beam fatigue life is analyzed based on timing analysis and Paris equation. The results indicate that the number, locations and depths of cracks have important effects on the modal parameters and the fatigue life of the structure.