Abstract: Laser-arc composite heat source welding technology integrates the high energy density and high efficiency of laser welding with the strong adaptability and mature process advantages of arc welding, achieving wide application in fields such as new energy vehicles and aerospace. However, due to the limitations of different arc types （such as TIG, GMAW, and plasma arc） in their working principles, there are still differences in adaptability and inherent welding defects （such as pores, unstable heat input, and energy coupling failure） in specific scenarios. Therefore, this paper focuses on three types of composite welding technologies: laser-TIG, laser-GMAW, and laser-plasma arc. It systematically reviews their research status, summarizes the defects derived from the arc characteristics of each type and the targeted solutions, and further looks forward to the development direction of this technology in process optimization and engineering application.