This research is one of the most important parts of the national 863 high tech project–“Robot and Detection technology in seabed oil pipeline”. The main task of the project is to develop an intellgent system which will be used for in-line inspection of seabed oil pipelines. This thesis introduces the ultrasonic detection principle briefly and analyzes the system technology parameters, then designs a special ultrasonic probe and sensor array for the testing by theoratical calculation and analysi...