The work aims to study different failure forms of remanufactured parts with different thickness of coatings in four-point bending fatigue test. The parts were remanufactured by performing arc spraying and then four-point bending test was performed. Fracture morphology of the remanufactured parts with different thickness of coatings was observed with scanning electron microscope, and initiation, growth and fracture mode of fatigue cracks on different thickness of coatings were studied. Initiation form of the fatigue cracks was found to be mainly multi-source failure fatigue. In the growth process of fatigue cracks, fatigue cracks growing in different planes intersected and formed shape of steps. When coating thickness was 100 μm and 200 μm, crack initiation mainly occurred between the coating and substrate in position bearing the most concentrated stress in the four-point bending test. And the cracks gradually expanded to the coating and substrate until the sample fractured. When coating thickness was 300 μm and 400 μm, crack initiation mainly occurred on both sides of the position bearing the maximum stress in the four-point bending test. The cracks spread symmetrically, connected on interface and led to layering of the coating and substrate. Later cracks in layered positions grew along the direction of substrate until the sample fractured. Failure mode of the whole system varies with coating thickness. For thin coatings, crack mode is mainly cracks perpendicular to coating-substrate interface, and tension failure dominates. For thick coatings, crack mode is mainly interface crack, and shear failure dominates.