Abstract: In order to study effect of laser welding on the properties of dissimilar metal welding joints of K418 and 0Cr18Ni9, microstructure and morphology of the weld were analyzed by using a metallographic microscope. The hardness and strength of weld seams and their surrounding area were evaluated. The results show that when laser welding of K418 superalloy and 0Cr18Ni9, there are great differences in thermal parameters of the base metal. In order to guarantee weld quality, laser spot should be biased on the side of 0Cr18Ni9 alloy. In order to prevent thermal cracks and liquation cracks, coagulation time of the melted pool should be prolonged as far as possible and heat input with heat effect should be reduced simultaneously. The protection of weld seam is the best when protection gas flow rate is 12L/min. Compared with Ar₂, N₂ can effectively reduce the porosity in weld seams, and it also reduces the weld performance. The hardness of the weld is between the hardness of two base materials. The strength of the weld joint is about 89% of that of the base metal. Good welding quality of K418 alloy and 0Cr18Ni9 can be achieved by adopting suitable laser welding process.