With the increasing global energy demand, ocean risers play a crucial role in the transportation of marine oil and gas resources as the main connecting component between offshore platforms and subsea wellheads. However, under the combined action of internal transport medium and external environment, marine risers are prone to corrosion damage, especially expansion and bending corrosion defects. This defect can lead to thinning of pipeline wall thickness, decreased pressure bearing capacity, and ultimately may cause serious accidents such as breakage and perforation of marine risers, resulting in environmental pollution and economic losses. In view of the problems of insufficient bending detection capability and low detection efficiency in existing multi-section pipelines, single-section detection design was adopted, and array ring probe was used as the core detection component to develop the first set of 12-inch single-section pipeline array ultrasonic internal detector with independent intellectual property rights in China. The detector passed the test of Tianjin Key Laboratory of Submarine Pipelines, and the detection performance met the requirements of the contract specification. Subsequently, CNOOC Wenchang 132B to 116 sea pipe 12 inch sea pipe pigging and internal inspection work was completed.