Abstract: Piezoelectric ultrasonic pipeline corrosion detector is a kind of internal testing equipment which makes use of ultrasonic wave to detect the corrosion situations of in-service long-distance pipelines. A structurally reasonable supporting structure of piezoelectric ultrasonic detector is the prerequisite for the success of pipeline corrosion detection. In this paper, the modal analysis was conducted on the 3D model of the supporting structure under the prestress state by the FEM based structure analysis software. It is indicated that the natural frequency of the supporting structure under the effect of prestress is higher than that in the natural state, but it is closer to the true natural frequency of the structure. Then, vibration test was carried out on the supporting structure. And it is verified that the simulation analysis is reliable and the error between the experimental result and the simulation result is mainly derived from the simplification of the supporting structure model. In conclusion, the research results are of great significance to the research and development of integral piezoelectric ultrasonic pipeline corrosion detector.