Abstract: Aiming at the problem of low detection efficiency of extruded bars, this paper analyzes the difficulties of extruded bar inspection and a robotic ultrasonic nondestructive testing system for extruded bars is therefore proposed. The system can be functionally divided into two parts: motion control of the test piece and ultrasonic testing. After experimental verification, the system can accurately identify the defects in the extruded bars with high efficiency and fast detection speed, which has a greater application prospect.