Abstract: In order to study the fatigue behaviour of steel plate-concrete composite decks, the paper conducted unvaried amplitude fatigue tests of ten specimens, and then, examined the influence of three main factors including stud layout, the number of PBL connecters and fatigue load level, on the failure modes and fatigue damage degree of composite bridge decks. During the experiments, the dynamic deflection, strains of concrete and steel plate, residual deflection and residual bearing capacity were measured. From the test results, it can be concluded that the service life of composite bridge decks is closely related to the margin of the fatigue stress of plain steel and the number of PBL connecters, while the stud layout has little influence on it. Composite deck specimens all failed in the mode of steel plate corrupture and concrete crushing under compression at certain fatigue load circle.