Aluminum alloy profiles based on laser-MIG hybrid welding were studied for high-speed trains, and the influence of different heat source angles on the welding characteristics, including appearance, pores and melt flowing, was investigated. Results show that the weld depth decreases with an increase in the angle between the laser and the welding direction. When the laser source angle is increased from 82.5° to 110°, the penetration depth and weld width decrease by 50% and 25%, respectively. Moreover, increasing the heat source angle is conducive for reducing the weld pores. When the laser source angle is increased from 82.5° to 97.5°, the weld porosity decreases from 3% to 0%. Moreover, the droplet transfer mode was observed under different heat source angles and the length of the molten pool was promoted by increasing the angle between the laser and the welding direction. Fluent simulation results suggested that the heat source angle has significant effects on energy propagation. With an increase in the angle between the laser and the welding direction, the propagation of energy in the depth direction will decrease. The heating range increases with increasing arc angle, which is beneficial for prolonging the solidification time of molten pools and the eliminating weld pores.