Abstract: To replace manual implementation of pipeline weld seam detection, a composite pipeline weld seam penetration detection robot was designed, and the system composition of the robot was introduced. The end tool of the system adopted a composite structure and had a quick change form. To verify the flexibility of the robotic arm in implementing automatic penetration technology, a 7-degree-of-freedom kinematic model of the robotic arm was established, and a normalized method was used to plan the arc trajectory of the wiping and spraying processes. The process implementation capability was verified in a simulation environment. Finally, the robot detection of composite pipeline welds was achieved through robotic arm planning and control, and the feasibility of the penetration detection process of the robot system was verified through sensitivity testing of the penetration process.