Abstract: The flow of the molten pool during tungsten inert gas (TIG) welding has an important impact on the final geometry, microstructure, residual stress of the weld, and understanding the flow characteristics of the molten pool had a great significance to control the quality and properties of the weld. At present, the research methods of molten pool flow characteristics are mainly divided into experimental test, numerical simulation and dimensional analysis. The status of research methods of the molten pool flow characteristics during TIG welding are summarized, and the characteristics of different research methods are compared and analyzed. The future research direction is prospected.