The effect of the technological features of laser welding of titanium-aluminium structures on the microstructure formation in welded joints is investigated. As revealed, for the increasing of laser radiation usage efficiency and elimination a threshold effect of reflection–absorption by aluminium surfaces, it is expedient to weld titanium alloys with aluminium in such a way that partial melting of the aluminium alloy is carried out on account of melting the titanium alloy. As proven, a suitable type of welded joint is an overlap joint with the location of the titanium part on top and the aluminium one—on the bottom. By means of analytical scanning electron microscopy and energy dispersive analysis, it is revealed that along the entire fusion line of the welded joint, there is an intermetallic layer, the thickness of which depends on the welding mode. As shown, when the laser welding process is produced with an overlap of 6 mm and heat input of 350–400 J/mm, the thickness of this layer is minimal and is 1–5 $\mu$m. An increase in the heat input value above 400 J/mm or a decrease in the amount of overlap is not advisable because of increasing in the thickness of intermetallic layer up to 25–100 $\mu$m. This, in turn, leads to a decrease in the level of mechanical characteristics. When choosing the technological modes of laser welding of overlap joints of titanium alloys with aluminium ones, it should be guided by the criterion of minimizing the size of the intermetallic layer. To reduce the brittleness of the joint and increase its mechanical characteristics, the size of this area should not exceed 10 $\mu$m.