Laser-CMT hybrid welding-brazing experiments were carried out on Al/steel dissimilar metals using AlCu filler wire in this work. The effects of welding parameters on the weld formation were systematically studied, and the hardness distribution, microstructure and tensile properties of the joints were also researched. The results indicated that increasing laser power, increasing wire feeding speed or reducing welding speed could improve the wetting and spreading of aluminum on the steel side, and the optimized welding parameters were obtained: laser power 2 100 W, wire feeding speed 4.0 m/min, and welding speed 1.0 m/min. The intermetallic compounds showed a double-layered structure, with lath-shaped near the steel side and needle-tip-shaped near the aluminum side. The thickness of the intermetallic compounds layer was about 2.1 μm under the optimized welding parameters, and the phase compositions of the intermetallic compounds were Fe4Al13, Fe2Al5, FeAl3, and Al2Cu. The average tensile strength of the joints was 164.9 MPa, which was 67.3% of the aluminum alloy, and the fracture mode was transgranular and intergranular mixed fracture.