Abstract: Narrow gap welding technology has become the first choice for welding thick plate structures in modern industrial production. Its technical and economic advantages determine it to become one of the main directions of the future development of thick plate welding technology. In recent years, with the continuous exploration and research and the development of scientific and technological workers, a variety of narrow gap welding methods have emerged. In this paper, narrow gap welding manufacturing technology is systematically described, introducing the narrow gap welding manufacturing technology such as electric arc welding, laser welding, and laser-arc hybrid welding. Meanwhile, this paper outlines the factors influencing the quality and efficiency of the manufacturing process of narrow gap welding with different heat sources, and summarizes the process characteristics and application areas of narrow gap welding with different heat sources. Subsequently, combined with the development status of related technologies at home and abroad, this paper summarizes the problems faced by narrow gap welding manufacturing technology and puts forward subsequent development proposals, with a view to providing references for researchers in related fields.