Abstract: The zero block of a long-span railway prestressed concrete continuous beam bridge is usually equipped with dense steel mesh, prestressed pipes, support anchors, anti-falling beam stop anchors and other components. During the concrete pouring of zero block, the coarse aggregate is not easy to pass through the reinforcement mesh, resulting in non compactness and other defects in the concrete of zero block. Elastic wave tomography technology can effectively detect the internal noncompactness of block zero, and its detection efficiency and accuracy can meet the engineering requirements. However, the traditional elastic wave tomography technology can only be applied to the regular rectangular interface, and can not effectively detect the curved interface. Based on the traditional elastic wave tomography technology, this paper proposes the curved interface tomography technology according to the actual engineering, and verifies the technology through field testing.