Abstract: As a high efficient and high quality welding technology,laser-arc hybrid welding technology has many advantages such as high speed,high efficient,high process stability,small distortion and one side welding with back formation and so on,and has wideprospect of engineering application. In laser-arc hybrid welding process,shape and property can be controlled,which was summarized and discussed from the coupling characteristics of thermal field,physical characteristics of arc,and weld pool and so on. The summaries in this paper can provide the theoretical support on engineering applications. Being combined the Industrial infrastructure and technical requirements in China,the application of laser-arc hybrid welding technology in engineering machinery,military industry,coal machinery and rail transit industry were introduced in detail,its comprehensive advantages in investment,efficiency and energy saving and environment-protection were analyzed.