The preparation of steel/aluminium composites by the impact jet solid-liquid composite method was studied. The surface of the steel matrix was pretreated in advance, and the moving speed of the steel matrix was changed during the casting process, resulting in different degrees of enhanced heat exchange between the molten aluminium and the steel matrix. The microstructure, morphology, composition and thermal conductivity of the steel/aluminium composite layer were detected and analysed via SEM, XRD, EDS and thermal conductivity, and the shear strength was measured via a universal testing machine. The experimental results show that with increasing moving speed of the steel matrix, the heat transfer of the impact jet of the molten aluminum on the steel matrix decreases. The composite interface is composed of Fe/Al intermetallic compounds, and the galvanized layer on the surface of the steel matrix plays the role of wetting, diffuse flow and protection, which effectively improves the bonding strength between the steel and aluminum. At a casting temperature of 810 ℃ and a moving speed of the steel matrix of 12 mm/s, the measured bonding strength is 19.1 MPa, and the highest thermal conductivity is 88.23 W/(m · K).