To address challenges related to gas leakage, pipeline corrosion, and the complexities of leak detection and plugging in gas pipelines, we have developed an advanced robotic system capable of detecting leaks and performing pressure plugging in live gas pipelines without the need for halting gas flow. This system leverages mature robotics and vision technologies to provide reliable online leak detection and intervention. The robotic system employs acoustic imaging technology to accurately locate leakage points and performs pressurized leak-sealing operations under manual remote control, ensuring effective intervention even in challenging pipeline conditions. A detailed description of the robotic system’s workflow for leak detection and sealing is provided, along with an in-depth analysis of its technical specifications. Additionally, a novel plugging device model, grounded in gum plugging technology, is designed to enhance sealing efficacy under pressure. Experimental validation demonstrates that the robotic system accurately identifies leak locations and achieves effective and efficient leak repair, confirming its reliability for real-time applications.