Through splitting tensile fatigue tests of asphalt concrete with polyester fiber of different fraction by volume and aspect ratio under stress control mode，the decay characteristics of fiber reinforced asphalt concretes stiffness modulus were determined. Combined the test results with the damage mechanics theory, the fiber reinforced asphalt concretes fatigue failure criterion was put forward. The fatigue life calculation method of asphalt concrete is established based on the S N equation, which takes into account the influence of fiber content characteristic parameter. The experimental study and theoretical analysis show that, the fiber content characteristic parameter can comprehensively reflect the influence of the fraction of fiber by volume and aspect ratio of fiber on the fatigue performance of asphalt concrete. Within the scope of the test, the optimum fraction of fiber by volume, aspect ratio of fiber and fiber content characteristic parameter in AC 13F are 035%, 324 and 113 respectively.