Abstract: The brazing performance of brazing filler metals AlSi12 and AlSiNi was analyzed by means of wetting test and thermal analysis. The microstructure, fracture morphology, phase composition and mechanical property of aluminum/steel joints brazed by AlSi12 and AlSiNi were analyzed by means of SEM, EDS and tensile strength test. The results showed that the wettability of AlSiNi filler metal is better than that of AlSi12, but the melting regions slightly enlarged. The thickness of the intermetallic compound layer in the AlSiNi brazing joint is 8.1 μm, which is thinner and more uniformly distributed than that in the AlSi12 brazing joint. The Ni-containing intermetallic compounds in AlSiNi brazing joint have better plastic toughness and stronger bonding force with steel. As a result, aluminum/steel brazing joint with AlSiNi has higher tensile strength than that with the AlSi12 joint.