Abstract: Welding visualization process is consisted of three parts of visual detection, information processing and intelligent control. In this paper, different visualization methods corresponding to specific detection signals were summarized, such as image detection method, infrared thermal image method, non-destructive testing visualization based on weld defect imaging and measurement visualization based on molten pool vibration. Then, the advantages and disadvantages of active visual method and passive visual method were compared from different perspectives. The development methods of information processing software and the application of image processing technology in the welding visualization were introduced, and different intelligent control methods applied during the welding visualization process were described. A positive expectation and prospect for the development of welding visualization technology in the future was given.