Abstract: Laser welding-brazing experiments of 5A06 and TC4 were carried out and AlSi12 was used as filler metal.The heat transfer in the process was analyzed and the three heat source models were established.With the heating of laser vertical beam, declining beam, off-center beam and rectangular beam, the joint temperature field of Al/Ti dissimilar alloys was calculated and analyzed by finite element method.The simulated results indicate that the temperature distribution is dissymmetrical obviously on the two sides of the seam.It can avoid the local overheating at the interface of titanium alloy that the laser spot center deviation from the seam centerline to aluminum base metal side is 0.40.6 mm.With elliptical spot heating, the temperature history of the joint is similar with the situation of circle spot heating, and with rectangular spot heating, the temperature difference between the joint!interface upper part and bottom is reduced.