Laser-arc hybrid welding technology is one of the research focuses in the high-energy beam welding areas, and also the optimal welding method for heavy- gauge steel (thickness not less than 5 mm). This paper systematically introduces the research progress of domestic and foreign researchers and companies in the laserarc hybrid welding of steel, and our latest research work on fiber laser- arc hybrid welding ofnew nano- scale strengthened steel (yield strength of 600~700 MPa) steel is briefly described. Finally, the heavy- gauge steel laser-arc hybrid welding technology research directions are analyzed and discussed.