The three point bending fatigue tests of AC 13I rubber asphalt mixture were carried out. The dissipated energy ratio(DER) was used to define damage variable and the damage evolution process was analyzed. The relations between dissipated energy(DE) and DER, and fatigue cycle number of the asphalt mixture were established. The fatigue equation based on the plateau value(PV) of DER was established too. The results show that the fatigue life decreases in power function with the increase of PV. The average relative error of the fatigue life predicted by the fatigue equation and the actual fatigue life is 933%, which indicates that the established fatigue equation can well predict the fatigue life of AC 13I rubber asphalt mixture. It is verified that the established relations and fatigue equation are also applicable to base asphalt mixture.