Tension-compression fatigue test of LTX 1240 fiber/epoxy composite was studied in this paper. The fatigue life was predicted by plotting S-N curve, fracture surface were observed in SEM, and the failure mode was analyzed. The results show that the conditional fatigue limit of the composite laminates is 278MPa. The failure process is the first resin matrix failure, and then generate interface stratification and even the tensile and shear failure of the fiber, then the interactings form the dispersion damage zone lead to the material fracture occurred.