Abstract: The effect of laser linear energy on the weld formation, microstructure and mechanical properties of 2 mm thick 0Cr18Ni10Ti austenitic stainless steel laser welding was studied. The mechanism of laser linear energy on the joint quality was obtained. The results show that with the increase of laser linear energy, the oxidation degree of weld surface gradually increases, the weld back reinforcement decreases gradually, and the metal spatter phenomenon intensifies. The increase of linear energy makes the weld microstructure coarsen and the width of heat affected zone increase. When the laser linear energy is bigger than 70.59 J/mm, the tensile strengths of the joints are bigger than that of the base metal, the specimens are all broken at the base metal. The microhardness distribution of laser welded joint is M-type, and the microhardness of fusion line is the maximum, and the hardness of the weld center is bigger than that of the heat affected zone.