Abstract: To identify the parameters of laser-arc hybrid welding process for large-diameter oil/gas pipelines, theoretical analysis and comparative tests are conducted to study impacts of such parameters as arc voltage, wire delivery speed, laser intensity, defocusing amount, laser incident angle, and laser-arc distance on forming and quality of welding operations. Moreover, set reference values for the parameters are proposed. Research results show that the laser-arc hybrid welding has a complex mechanism and its numerous welding parameters have interactions during welding operations. To identify optimal welding processes, all these parameters shall be analyzed systematically. In fact, there are multiple sets of parameters available to achieve satisfactory welding performances. Through in-depth researches for mechanisms of the laser-arc hybrid welding, multiple process parameters suitable for different working conditions can be identified. Relevant research results may provide guidance for application of the laser-arc hybrid welding process in pipeline industry.