Abstract: The oscillating laser welding was carried out for 3D-GH3625 nickel-based superalloy with 4.7 mm thickness,and the effects of oscillating amplitude and oscillating frequency on the porosity and macro-morphology of the base metal,microstructure and mechanical properties of the joints were studied. The results indicate that when the oscillating frequency is fixed at 100 Hz or the oscillating amplitude is fixed at 2 mm, the porosity of the weld gradually decreases to 0 with the increase of the oscillating amplitude or oscillating frequency, and the macro-morphology of weld metal gradually changes from "Y" type to "V" type. The welded joint consists of the base material, the heat affected zone and the weld metal, and the heat affected zone is narrow. The welded microstructure is mainly columnar crystals. With the increase of the oscillating amplitude or oscillating frequency, the growth direction of the columnar crystals gradually shifts from the weld center to the weld surface. The columnar crystals are composed of dendritic γ phase and interdendritic precipitates of γ' phase. Under different oscillating parameters, the hardness of the weld metal is generally lower than that of the base material. Compared with the small oscillating amplitude, the large oscillating amplitude slightly increases the average hardness of the weld metal to 255.0-257.4 HV, while the increase of the oscillating frequency has no obvious effect on the average hardness of the weld.Tensile fractures are consistently located within the weld zone, and the tensile strength is negatively correlated with the porosity. The tensile strength of the joints without pores is 944.1-971.0 MPa, and the tensile strength of the joints with an oscillating amplitude of 3 mm is slightly reduced. The microscopic fracture morphology of the non-pore area of the joint tensile specimen is mainly dimple.