The invention discloses a method for improving the performance of an aluminium alloy laser welding head. The method comprises the following steps that A, grooves are formed in the welding faces of to-be-welded aluminium alloy plates; B, TiB2 particles are added in the grooves, and then two to-be-welded aluminium alloy plates containing the TiB2 particles are spliced; C, the weld joint of the aluminium alloy plates spliced in the step B is subjected to laser welding. According to the method, the prefabricated TiB2 particles are evenly distributed in the weld joint according to the stirring effect of small holes on a molten pool in the laser welding process, the purpose of improving the strength of a joint is achieved by depending on the strengthening effect of the TiB2 particles on aluminium alloy, accordingly, the strength of the welding joint is obviously improved and can be even better than the performance of base metal.