The fatigue performance of E-glass fiber/epoxy reinforced polymer in transmission tower bars was investigated. The fatigue limit load of the material is performed in Up-down method followed by the analysis of the fatigue limit load and the displacement of the specimens. The results show that the fatigue limit stress of specimens is 246.75 MPa under 105 times in cyclic loading, the displacement amplitude of specimens increasing with loading adding is between 3.8mm and 4.9mm, the fatigue damage of specimens occurs at the joint due to the strength of which is lower than that of the material. Therefore it should pay attention to the strength of connections to meet the practical requirements under the fatigue.