With the increasingly use of FRC (fiber-reinforced composite) in urban lifelines, me-chanical properties investigation is very important for disaster resistance, especiallythe investigation of fatigue properties. Based on the shear-lag model, an usual com-posite model under cyclic loading is established. According to the Paris formula, therelationship between interfacial fatigue parameters and the number of cycles is ob-tained under the cyclic loading. Interfocial fatigue properties of this model and thegrowth of the interfacial fatigue crack are analyzed. And the Poisson ratio is consid-ered also. With the increasing use of FRC (fiber-reinforced composite) in urban lifelines, me-chanical properties investigation is very important for disaster resistance, especially the investigation of fatigue properties. Based on the shear-lag model, an usual com-posite model under cyclic Loading is established. According to the Paris formula, therelationshipbetween interfacial fatigue parameters and the number of cycles is ob-tained under the cyclic loading. Interfocial fatigue properties of this model and the growth of the interfacial fatigue are analyzed. And the Poisson ratio is consid-ered also.