Vision-based sensors play an essential role in robotic welding, which attract increasing attention by scholars because of its non-contact characteristic, high precision, fast detection, and strong adaptability. This paper summarizes the recent research developments of vision sensor-based intelligent robotic welding and analyzes their characteristics and application scenarios in the welding process. The applications of vision sensing technologies are illustrated, especially in visual calibration, initial welding position guidance, weld seam tracking, weld pool monitoring, correlation deformation detection, and defect identification. At the end of this paper, the promising development directions of intelligent robotic welding technologies are discussed, including the hardware developments of vision sensors, optimization of image processing algorithms, the combination of passive vision and active vision, multi-sensor information fusion, and applications of artificial intelligence.