The microstructure and properties of the joint were studied, based on the trial of twin spot laser welding of 2 mm thick 1420 aluminium-lithium alloy. The characteristics of microstructure, micro-hardness, room-temperature tensile strength and fractography of both twin spot and single spot laser welded joints were compared. The results indicate that the microstructures of the joints by twin spot and single spot laser welding are similar. Equiaxed grains, columnar crystals, and equiaxed dendrite crystals can be found from fusion zone to the weld center in the twin spot welded joint, which are finer than that of single spot welded joint. The microhardness of twin spot laser welded joint is higher than that of single spot laser welded joint, but lower than that of base metal. Meanwhile, the tensile properties of twin spot laser welded joint is decreased to 86% of that of base metal, but a little higher than that of single spot laser welded joint