Abstract: A 10 kW laser was used for laser-arc hybrid welding of a low-carbon bainite steel with a thickness of 10 mm.The influence of laser power, wire feeding speed and welding speed on the forming was investigated. The welding process was optimized, and the microstructure of each region, hardness, tensile and impact mechanical properties of the joint were studied.The results show that the optimized process parameters can be determined as laser power of 4.0-4.3 kW, wire feeding speed of 13-13.5 m/min, welding speed of 14-15 mm/s. The microsturcture of the weld metal is mainly lath bainite, acicular ferrite and a small amount of martensite, the microstructure of the heat affected zone is mainly lath and granular bainite, and a few M-A components, ferrite, martensite. Due to the heat cycle of welding, there is a significant difference in hardness. The hardness of the heat affected zone is the highest, followed by the weld, both of which are higher than that of the base metal.The tensile failure of the welded joint is at BM away from the weld, and there is obvious necking phenomenon at the fracture location, the welded joint has good tensile properties. Compared with that of the base metal, the impact toughness of each micro zone is significantly reduced, that of the heat affected zone is better, and the weld has the lowest impact toughness;overall, the weld zone has high strength and low toughness, while the heat-affected zone has low strength and high toughness.