Accompanied by the continuous development of oil and gas pipeline testing technology, the long-term, safe and stable operation of oil and gas pipelines has become an important factor restricting its rapid development; the pipeline from time to time experiences leakage accidents due to corrosion and thinning, so for the station pipeline, monitoring the wall thickness of corrosion-prone parts is very important. This paper proposes a kind of intelligent corrosion ultrasonic monitoring system design for oil and gas station pipelines, and practice and application in the field. Firstly, through theoretical analysis, the basic principle of thickness measurement based on ultrasonic reflection method is analysed. Then, the design of the ultrasonic online monitoring system was completed through the electronic integration modular design and the development of the ultrasonic pipeline thickness measurement background management system cloud platform. In order to achieve high-precision wall thickness monitoring of oil and gas pipelines under predetermined temperature conditions, a constant-temperature ultrasonic thickness measurement experiment was carried out in the laboratory, and linear regression fitting was carried out on the system’s thickness measurement data and manual thickness measurement data. The actual on-site thickness measurement experiments show that: the system achieves effective online continuous monitoring of pipelines in the station yard, carries out analysis and processing of the monitoring data in a remote area and is capable of realising high-precision monitoring within the specific measuring range. The system provides a new idea for intelligent corrosion monitoring in oil and gas stations.