A multi-group lens assembly, comprising: at least a first group unit that includes a first supporting component and a first group lens, wherein the first group lens is mounted on the first supporting component; at least a second group unit that includes a second supporting component and a second group lens, wherein the second group lens is mounted on the second supporting component, and when the first group unit is mounted on the second group unit, the first supporting component is supported by the second supporting component; and a welding structure (20, 20', 20") that includes at least a first welding part (21, 21A, 21B) and at least a second welding part (22, 22A, 22B) that is welded and fixed to the first welding part (21, 21A, 21B), wherein the first welding part (21, 21A, 21B) and the second welding part (22, 22A, 22B) are provided on the first supporting component and the second supporting component, respectively, characterized in that the first welding part (21, 21A, 21B) and the second welding part (22, 22A, 22B) are made of a metal material and fixed to the first group unit and the second group unit by means of embed-molding, respectively, wherein the first welding part (21, 21A, 21B) includes a first embedding portion and a first connecting portion connected to the first embedding portion, and when the first welding part (21, 21A, 21B) is embedded into the first supporting component, the first embedding portion is embedded into the first supporting component and the first connecting portion forms a first exposed surface, wherein the second welding part (22, 22A, 22B) includes a second embedding portion and a second connecting portion connected to the second embedding portion, and when the second welding part (22, 22A, 22B) is embedded into the second supporting component, the second embedding portion is embedded into the second supporting component and the second connecting portion forms a second exposed surface, and the first exposed surface of the first connecting portion and the second exposed surface of the second connecting portion are bonded to each other after the first welding part (21, 21A, 21B) is welded to the second welding part (22, 22A, 22B), wherein the second embedding portion is a protrusion extending radially from the second connecting portion. at least a first group unit that includes a first supporting component and a first group lens, wherein the first group lens is mounted on the first supporting component; at least a second group unit that includes a second supporting component and a second group lens, wherein the second group lens is mounted on the second supporting component, and when the first group unit is mounted on the second group unit, the first supporting component is supported by the second supporting component; and a welding structure (20, 20', 20") that includes at least a first welding part (21, 21A, 21B) and at least a second welding part (22, 22A, 22B) that is welded and fixed to the first welding part (21, 21A, 21B), wherein the first welding part (21, 21A, 21B) and the second welding part (22, 22A, 22B) are provided on the first supporting component and the second supporting component, respectively, characterized in that the first welding part (21, 21A, 21B) and the second welding part (22, 22A, 22B) are made of a metal material and fixed to the first group unit and the second group unit by means of embed-molding, respectively, wherein the first welding part (21, 21A, 21B) includes a first embedding portion and a first connecting portion connected to the first embedding portion, and when the first welding part (21, 21A, 21B) is embedded into the first supporting component, the first embedding portion is embedded into the first supporting component and the first connecting portion forms a first exposed surface, wherein the second welding part (22, 22A, 22B) includes a second embedding portion and a second connecting portion connected to the second embedding portion, and when the second welding part (22, 22A, 22B) is embedded into the second supporting component, the second embedding portion is embedded into the second supporting component and the second connecting portion forms a second exposed surface, and the first exposed surface of the first connecting portion and the second exposed surface of the second connecting portion are bonded to each other after the first welding part (21, 21A, 21B) is welded to the second welding part (22, 22A, 22B), wherein the second embedding portion is a protrusion extending radially from the second connecting portion.